DE2157810C2 - Bituminous compounds for use as a self-adhesive layer when exposed to light pressure - Google Patents

Description

From GB-PS 12 01 135 hot-processable bitumen mixtures are known, which are less than 15 Contain percent by weight of block copolymers and can also be used as hot melt adhesives. For gluing and gluing roofing materials, the proportion of the block copolymer component must be 63 to 143 percent by weight and the bitumen component should penetrate at 25 ° C in the range from 40 to 550 (in 0.1 mm). For use in road construction, the The proportion of the block copolymer, however, is less than 10 percent by weight and the Bitumen component should penetrate at 25 ° C in the Range from 50 to 500.

In addition to its penetration value, the bitumen component is characterized in that its aromatic character, expressed as the proportion of aromatic carbon in the n-heptane malt phase (fa), is higher than the value of 0.004 χ Px 0.280 (P " content of the n-heptane asphaltenes The block copolymer components are compounds of the structure

A-B-A

in which the two blocks A represent the same or different thermoplastic, non-elastomeric polymer blocks, which by polymerization at least one have been prepared monovinylaromatic compound, and the block B one, optionally in whole or means partially hydrogenated, elastomeric polymer block, which either by polymerization at least of a conjugated diene or by copolymerization of at least one conjugated diene with at least a monovinyl aromatic compound

The aforementioned adhesives and other known adhesives are often in the form of Solutions in organic solvents applied to the substrate or carrier. The usage however, this solution has disadvantages, e.g. B. blistering, easy flammability and health hazard. The production is furthermore inhibited by the fact that the evaporation of the solvents is time consuming.

The use of the adhesives in the form of hot melts is also associated with disadvantages, especially when working on the roof of buildings. The adhesives must generally first near the roof or on the roof on which they are to be applied, be heated, and then the hot mass must be applied to the roof. Then it can roofing material mostly present in sheet form at a time when the adhesive is still is sufficiently flowable, be glued to the roof. When the temperature of the adhesive is too high

Has dropped, it is practically impossible to mass apply evenly to the roof. The procedure therefore requires precise timing as it is time consuming and demanding on the labor force It is also very difficult to just in Handicraft, e.g., using a broom, a To achieve regular coating of the roof.

In NL-OS 67 14 269, adhesive layers based on a pressure are already used when pressure is applied (blown) bitumen and a natural or synthetic rubber described · However, it was found that such masses in some respects, e.g. B. regarding peel strength, adhesiveness and high temperature storage resistance, does not always bring satisfactory results.

Such pressure-sensitive adhesives, also known as "self-adhesives", must be ^{sufficiently flowable below 200 3} C to be applied in the form of a melt to a carrier by conventional methods, e.g. with any suitable application device, such as a roller or pouring device will. In this case, it is possible to achieve a high degree of accuracy in the thickness of the applied layer of adhesive, while there are no locations that are not covered by the adhesive.

In the case of pressure-sensitive adhesives, the adhesiveness is based inter alia. on properties such as B. the Surface thickness, tensile strength, viscosity and hardness. The adhesion depends on time and pressure. Such adhesives can, at temperatures not too far removed from room temperature, as in Range from -10 to 80 ° C, preferably from 0 to 40 ° C, can be used. At the temperature at which the coated with the pressure-sensitive adhesive Objects are used, e.g. B. at 25 ° C, the viscosity of the adhesive to ensure a more sufficient: peel strength more than 5000 poise and less to maintain sufficient tack than 500,000 poise.

The object of the invention was to provide a self-adhesive layer for use as a self-adhesive layer when exposed to slight pressure to provide suitable bituminous compounds. This object is achieved by the invention.

The bituminous masses used according to the invention for this purpose have the composition according to the main claim.

In the figure mentioned in the main claim, the values on the ordinate are logarithmic, on the The abscissa is plotted on a linear scale.

The method according to ASTM test standard D 5 is used to determine the penetration value

The proportion of the aromatic carbon of the n-heptane Malten phase (fajwlrd according to a method described by RB Williams in "Proceedings, Sixth World Petroleum Congress", Section V (1963), Paper 17, from the relative density of 20/4 and the percentages of the Carbon and hydrogen determined

Examples of objects, which with a layer of these bituminous masses according to the invention can be provided are shingles or sheets of roofing materials, especially synthetic Roofing materials, labels or foils, insulating tapes for electrical devices, medical Adhesive tapes and tapes for other purposes.

This Ausfühnnigsform is particularly suitable for Materials with a low heat distortion temperature, such as sheets of various polystyrene, which on can be stuck on roofs in this way when cold.

Under certain conditions, good results are achieved in particular with bituminous masses in which the penetration value (25 ^° C.) of the bituminous component (a) is related to the block copolymer portion (b) in such a way that the mixture of the sides of the polygon ABCDEFG in the figure Area corresponds to where the vertices of the

ίο polygons the coordinates A ₁ B ₁ C, D (as described in the main claim), £ (14.5 / 85.5; 550), F (7.6 / 92.4; 200) and G (7.5 / 924; 150).

It has also been found that in regions with temperate climates, excellent results can be obtained if the relationship between the penetration value (25 ° C) of the bituminous component (a) and the block copolymer fraction (b) is such that the mixture of the sides of the square AHED corresponds to the area enclosed in the figure, the vertices of the quadrilateral AHED having the coordinates A (as described in the main claim), H (5.6 / 94.4; 400), and O (as described).

In general, the more pronounced the aromatic character of the bituminous component

(a) The better the storage stability and the flow properties of the bituminous masses at high temperatures. The proportion of the aromatic carbon of the n-heptane Malten phase (fa) of the bituminous component (a) is preferably in a range of values between higher than 0. OW χ + 0.280 and lower than 0.004 χ f + OßlO.

The bituminous component (a) consists largely of bitumen or mainly contains a bitumen. "Bitumen" is to be understood here as a dark, highly viscous to almost solid residue of a crude oil, which is obtained after the components have been separated off with higher volatility and has a penetration value (25 "C) of less than 2000 according to ASTM test standard D 5 will have at least 250 ⁰ C, bitumen, soft due to their low aromatic character are not suitable for preparing storage stable mixtures with Rlockcopolymeren may be prepared by the addition of aromatic components modified such that they, bituminous component should also have a flash point (open cup to Cleveland) can be used for the aforementioned purpose. Within the stated limits, the aromatic character of bitumen with a high aromatic content,

so which as such with block copolymers give storage-stable mixtures, but have a poorer resistance to flow than low-aromatic bitumen at higher use temperatures, are adjusted in such a way that mixtures with just sufficient storage stability and considerably improved resistance to flow at high use temperatures are obtained.
In the case of a cold climate, ie at low use temperature, it is often appropriate to use bituminous components with a relatively high penetration value z. B. from 500 to 2000 to use.

The bituminous components which can be used according to the invention can be produced from mineral oils

f> 5 will be. Preferred bituminous components are Distillation or straight-run bitumen, precipitated bitumen and mixtures of these bitumen, the mixing ratio being chosen so that the aromatic

see character corresponds to the aforementioned relationship and the penetration value (25 "C) is reached from 130 to 2000. Satisfactory results are achieved with Distilled bitumen obtained from crude oils from the Far East and California crude oils. >

Mixtures of at least one of the aforementioned can be used as bituminous components with great advantage Bitumen with aromatic petroleum extracts can be used, with such a quantitative ratio is used that the aromatic character of the m corresponds to the aforementioned relationship and the desired penetration value is achieved at 25 ° C. When a Bituminous component of this type is used, a mixture of a precipitated bitumen is preferably used and an aromatic petroleum extract used, π in particular a mixture of a propane bitumen and an aromatic extract of a heavy lubricating oil.

Furthermore obtained Erdölpe-> n before and coal tars may be used as admixtures for the bituminous component by cracking process.

The thermoplastic polymer blocks A of the block copolymers Α —Β —Α preferably have molecular weights from 7,500 to 100,000, in particular from 15,000 to 30,000. The elastomeric polymer block B is _ · -, either by polymerizing at least one conjugated diene or by copolymerization at least one conjugated diene with at least one monovinyl aromatic compound prepared. The elastomeric polymer block B also has preferred m wise a molecular weight of 25,000 to 1,000,000, in particular from 35,000 to 150,000. The proportion of thermoplastic polymer blocks A in the block copolymers is preferably 10 to 70 percent by weight, in particular 20 to 50 percent by weight. Examples π monovinyl aromatic monomers suitable for preparing blocks A and B are styrene and λ methylstyrene, while for the production of the blocks B as conjugated diene monomers, preferably dienes with 4 to 8 carbon atoms, in particular butadiene and isoprene, -in can be used.

Examples of block copolymers useful in the present invention are

Polystyrene / polyisoprene / polystyrene, polystyrene / polybutadiene / polystyrene, -r,

Polystyrene / partially hydrogenated polyisoprene / polystyrene,
Polystyrene / styrene-butadiene copolymer / polystyrene and polystyrene / hydrogenated polyisoprene / polystyrene. ><>

With regard to the oxidation resistance of the pressure-sensitive layers of the adhesive hydrogenated or partially hydrogenated block copolymers are expediently used, in particular those at where only the diene block B is hydrogenated, the thermoplastic However, blocks A are not hydrogenated. A polystyrene / polybutadiene / polystyrene block copolymer is particularly preferred or its hydrogenated derivative

The mixtures used according to the invention can be prepared in a simple manner, e.g. R through bo Stir in the polymeric component (b) as a finely divided solid substance or in the form of a solution, e.g. in Benzene or toluene, into the molten bituminous component (a). The solvent can afterwards be evaporated. e »

The high mechanical strength and weather resistance of synthetic roofing materials, such as sheets made of butyl rubber and ethylene / propylene rubber, allow the use of a single layer. If a according to the invention with the bituminous mass coated sheet from the roofing material by the action of z. B. low Temperatures and external forces have been detached from the roof, the bond between the web and the roof can be restored by applying pressure to the membrane. If necessary, the train will before applying pressure e.g. B. slightly heated to remove the moisture. Sheets of roofing materials are often delivered in the form of coiled rolls for transport and to facilitate handling. The pressure sensitive adhesive layer can in this case Cover films or tapes are protected with an adhesive-repellent surface. To generate the The adhesive-repellent surface can be impregnated with wax or adhesive-repellent organopolysiloxanes be made. You can also the back of the webs with organopolysiloxanes or coat other adhesive-repellent compounds and then roll up the sheets. Lanes or Tapes can also have a pressure-sensitive adhesive layer on both sides so that others can Materials adhere to both sides. To make handling easier, these two layers are used mostly protected by cover layers with an adhesive-repellent surface. The adhesive layer off the bituminous mass can also be provided on both sides with a cover sheet, so that after removal of the two outer layers only the self-adhesive layer remains, z. B. between two objects that should adhere to each other.

The mixture of the bituminous component (a) and the block copolymer (b) can also contain pigments, Compounds that influence the rheological properties of the mixture, such as glass or asbestos fibers, as well as inorganic and / or organic fillers customary for adhesives. Examples of suitable Fillers are lime, unfired powdered plaster of paris, diatomaceous earth and quartz flour. Furthermore, this can Mixture containing other conventional additives, such as oxidation inhibitors.

The thickness of the adhesive layer on the substrate or carrier in question can be determined with a high degree of accuracy can be set. The mixture of the bituminous component (a) and the block copolymer (b) can z. B. be applied in the form of a melt from above or below on the substrate, the Layer can then be removed with the help of squeegees until the desired thickness is achieved. The thickness of the layer depends on the particular application and can be within a wide range Area. It is generally from 0.0025 to cm. If the one provided with the adhesive layer If the substrate or carrier is to be applied to dusty surfaces, the thickness of the adhesive layer must be at least 0.025 cm, preferably 0.063 to 0.5 cm. For most purposes, one is enough Layer with a thickness of 0.063 to 0.4 cm, preferably from 0.23 to 033 cm. The desired Thickness can also be achieved by using two layers, each half the desired thickness will.

The pressure sensitive adhesive layer is preferably applied to pretreated, e.g. B. dried and Roughened, dust-free and oil-free surfaces applied To facilitate the application of the

bituminous mass this is sometimes diluted with aromatic-rich petroleum distillates or mixed-paraffin-naphthenic petroleum distillates. Before the If the coated object is used, the distillates must be evaporated. The example illustrates the invention.

example

There are 10 mixtures of bituminous components (a) and various block copolymers (b) with the the following composition:

Mixture I.

92 percent by weight 8 percent by weight

Mixture!!

92 percent by weight 8 percent by weight

Mixture III

88 percent by weight 12 percent by weight

bituminous component block copolymer A (commercial product)

bituminous component block copolymer B (commercial product)

bituminous component block copolymer A

Mixture IV

88 percent by weight bituminous component 12 percent by weight block copolymer B

Mixture V

92 percent by weight 8 percent by weight

Mixture VI

92 percent by weight 8 percent by weight

Table I.

bituminous component Blockeop '/. ymeres A

bituminous component block copolymer B

Mixture VII

87 percent by weight bituminous component 13 percent by weight block copolymer C (Commercial product)

For comparison tests: Mixture VIII

90 percent by weight bituminous component ίο 10 percent by weight block copolymer C

Mixture IX

80 percent by weight bituminous component 20 percent by weight block copolymer A

ι ί mixture X

96 percent by weight bituminous component 4 percent by weight block copolymer A

The following applies to comparative tests VIII to X:

Mixture Viii

the penetration value for the bituminous component is too low (see table I)

_? . Mixture IX

the penetration value for the bituminous component is too high (see Table I)

Mixture X

the proportion of the block copolymer component υ 'is too low.

The proportion of the block copolymer relates to the oil-free material. The bituminous component sets Mixture of a precipitated bitumen and an aromatic extract. The bituminous components of mixtures I to X have the properties shown in Table i.

Bituminous component
in the mixture

Penetration value (25 ° C), 0.1 mm fa the n-lleptane
Painting phase

Content of n-heptane asphaltenes,% by weight

I-IV; VII; X V; VI VHI IX

400

220

80

± 3000

Block copolymer A:

Styrene / butadiene / styrene block copolymer having a molecular weight of 20,000/100,000/20,000; the copolymer contains 16.5 percent oil;

Block copolymer B:

Styrene / isoprene / styrene block copolymers having a molecular weight of 30,000/150,000/30,000;

Block copolymer C:

Styrene / butadiene / styrene block copolymer with a molecular weight of 14,000/65,000/14,000.

In order for the mixtures to be suitable as pressure-sensitive adhesives, the peel strength should be a value of at least 0.5 kg / cm width (25 ° C).

The mixtures are applied as a layer with a thickness of 1 mm between two strips of material Peel strength (25 ° Q in kg / cm is based on tensile tests perpendicular to the surface of the webs 0.32 0.33 0.36 0.42

4.5 5.1 6.4 2.4

carried out (180 ° peel test). at When using plywood, the peel strength is determined perpendicular to the surface of the plywood (90 ° peel test). The following materials are used:

1 ethylene-propylene-dicyclopentadiene terpolymer / ethylene-propylene-dicyclopentadiene terpolymer; 180 ° peel test

2 butyl rubber / butyl rubber; 180 ° peel test 3 aluminum / aluminum; 180 ° peel test

4 butyl rubber / barrier wood; 90 ° peel test

5 aluminum / plywood; 90 ° peel test

6 Commercially available polymer based on tetrafluoroethylene / plywood; 90 ° peel test

The results of the peel tests are shown in Table II.

Table II

ίο

Mixture peel strength (25 ° C). kg / cm width

material

I 2 3

2.5 II 1.5 III 1.0 IV 1.5 V 4.0 VI 1.5 VIII *) ± 0.05 IX *) ± 0.1 X *) 0.2 *) Comparative tests.

1.0 1.0 0.7 0.5 1.0 1.0 1.4

3.2

± 0.05 ± 0.1 0.2

± 0.05 ± 0.1

For this purpose \ sheet drawings

Claims (3)

Patent claims: 1, Use of bituminous masses with a viscosity up to 25 "C in the range of more than 5000 to less than 500,000 poise than with light pressure self-adhesive layer, consisting of a mixture of (a) a bituminous component with a penetration value (25 ° C) of 130 to 2000, the aromatic character of the bituminous component expressed as the proportion of aromatic carbon of the n-heptane malt phase (fa) being greater than 0.004 χ Ρ + 0.230 ! 5 (P = content of n-heptane asphaltenes in the bituminous component), and (b) one, optionally fully or partially hydrogenated, block copolymers of the general formula Λ-Β-Α in which the two blocks A represent the same or different thermoplastic, non-elastomeric polymer blocks which have been produced by polymerizing at least one monovinylaromatic compound, and block B is an elastomeric polymer block which is produced by polymerizing at least one conjugated diene or by copolymerizing at least one conjugated diene T. it has been prepared with at least one monovinyl aromatic compound, the weight ratio of the bituminous component (a) to the bicopolymer (b) 95.5: 43) being 5 to 763: 23 ^ and also a relationship between the penetration value (25 ° C ) the bituminous component (a) and the block copolymer component (b) consists in such a way that the mixture corresponds to the area enclosed by the sides of the square ABCD in the figure, in which figure on the ordinate the penetration value (25 ° C) of the bituminous component ( in 0.1 mm) and on the abscissa the weight ratio of the block «Copolymers (b) to the bituminous component (a) are applied in the mixture, the vertices of the square ABCD the coordinates A (4 ^ / 953; 130), B (73/923; 2000), C (233/763; 2000) and D (133/863; 200). 2. Use of bituminous compositions according to claim 1, characterized in that the penetration value (25 "C) of the bituminous component (a) to the block copolymer portion (b) is in such a relationship that the mixture of the sides of the polygon ABCDEFG in the Figure corresponds to the enclosed area, the vertices of the V ^ leak the coordinates A ₁ B, C, «> Dfj according to claim 1), £ (143 / 85.5; 550), F (7.6 / 92.4; 200) and C (73>923; 150). 3. Use of bituminous masses according to claim 1, characterized in that the penetration ^{value (25 0} C) of the bituminous component (a) to the block copolymer portion (b) is in such a relationship that the mixture of the sides of the square AHED in the figure enclosed area, where the vertices of the quadrilateral AHED have the coordinates A (according to claim 1), H (5,6 / 94,4; 400), E (according to claim 2) and D (according to claim 1). 4, use of bituminous masses according to claim 1 to 3 as a layer for webs Roofing materials.