GB2045260A - >Bitumen Composition - Google Patents

Abstract

The invention relates to a bitumen composition suitable for coating purposes, as well as to the process for producing sealing compounds containing said compositions. The bitumen composition according to the invention comprises bitumen and linseed oil varnish, paraffin, stearin, and optionally a stabilising agent against oxidisation, polyisobutylene, spindle oil and a silicone resin. The composition prepared according to the invention is applied onto a soft cellular polyurethane substrate with open pores in such a manner that 2.5-4 parts of the product having the composition previously described are applied to 1 part of the substrate at a temperature of 60-90 DEG C. The coated substrate is cooled by air or it is allowed to cool. The sealant thus obtained is particularly suitable for use in the building industry and civil engineering for sealing gaps and as a waterproof product.

Description

SPECIFICATION Bitumen Compositions for Coating Purposes and a Process for Preparing Sealing Compounds The invention relates to bitumen compositions suitable for coating and to the process for producing sealing compounds containing such bitumen compositions. The sealing compounds are used especially in the building industry for waterproofing purposes.

Both in buildings and civil engineering structures there has been a continuously increasing demand for cheap sealing compounds to be easily manipulated, which are well suitable for sealing expansion gaps in e.g. walls. For said purpose several types of sealing compounds have been developed. One of these groups comprises homogeneous synthetic materials combined with sealing compounds, while another group comprises such sealing compounds which contain a sealant composition applied to an organic substrate. The desired impermeability to water can be achieved e.g.

by the combined application of a cellular polyethylene with closed (non-interconnecting) cells with cold sealants such as silicones, polysulphides, polyurethanes and polyacrylates. The disadvantage of the known technique lies in that production costs of cellular polyethylene with closed cells are high. The simultaneous application of the material is rather cumbersome, since the cellular plastic yields a satisfactory seal which is impermeable to water only if it is used together with a sealing compound.

On the other hand, sealing materials (sealing bands) containing cellular polyurethane are well known. These are prepared by means of diluted bitumen adjusted to the desired viscosity and by using cellular polyurethane as a porous substrate. For the purpose of waterproofing, cellular polyurethane bitumen is used in form of a solution prepared with an organic solvent. Such bituminous sealants have been widely used, particularly for the sealing of door and window frames, as well as for the sealing of gaps between panels on facings thereby protecting them from penetrating water, air and dust. For producing sealing material from soft cellular polyurethane serving as organic substrate, bitumen seemed to be the cheapest and most easily available material. In general, sealants prepared with bitumen meet the requirements prescribed for said materials.Dissolving the bitumen in organic solvents and the use of the solution for coating organic substrates have been known for a long time. In general, a fraction of a mineral oil, e.g. petrol has been used as solvent to dissolve the bitumen.

The production of a known sealing material is performed by coating pre-cut cellular polyurethane strips of the required size at 40 to 500C with a solution prepared with petrol and containing approximately 40% bitumen. The coated strips are lightly squeezed in order to remove the surplus of the bituminous solution; the sealing strips, still wet from the petrol, are then packed (in case of necessity they may be previously dried).

The bituminous solution prepared with petrol is inflammable and explosive, thus safe use of this technology requires the utmost care as well as continuous supervision. Serious damage to health and contamination of the environment may also occur. Due to the petrol content, the handling of the final product is very complicated, the appearance of the product is unfavourable, i.e. it is sticky, and slimy to the touch and it does not generally comply with the requirements of modern building industry.

The petrol-containing bitumen solution as a coating substance damages the cellular polyurethane substrate; further, in course of the drying process, removal of the solvent from the pores of the substrate involves considerable difficulties; and productivity is not at all satisfactory, not to mention its environment-contaminating effect.

The demands raised by the building industry and other industrial branches reiating to sealing materials are rather many-sided e.g. durability, impermeability to water, easy handling being amongst the most important. On the other hand, manufacturers of sealing materials try to reduce the costs of production to eliminate technologies involving fire and explosion hazard and contamination of environment, and simultaneously to increase productivity.

Undoubtedly, from the point of view of economy the combination of the bitumen suitable for coating and the substrate made of cellular polyurethane seems to yield an optimal solution. It goes without saying that the bitumen in itself-i.e. without dilution is quite unsuitable for coating the cellular polyurethane.

Accordingly, the aim of the invention has been to provide and produce, respectively, a bitumen composition, the properties of which can be varied within wide limits, which is suitable for coating a substrate without using any diluent for obtaining proper waterproof properties; furthermore, coating may be performed within the temperature range between 50 and 900C and in a relatively short time.

Besides-compared to known products-the sealing material produced is more suitable for proper use, since the total quantity of the coating composition applied onto the substrate is retained in the pores of the substrate.

A further requirement is that the waterproof properties of the coated polyurethane and its appearance should be superior to known products.

Accordingly, we intend to provide a bitumen composition which does not contain any solvent, the physical properties of which may be varied in dependence of the required use within relatively wide limits, comprising easily available additives, and which does not adversely influence the properties of the synthetic substrate in respect of durability and ageing.

The bitumen composition according to the invention, suitable for coating, can be characterised in that it contains bitumen and linseed oil varnish; the linseed oil varnish should be added in such a quantity that it should reduce the original viscosity of the bitumen-measured by means of a tarviscosimeter at 1 00C at least to 1/5th of its original value; furthermore, it contains stearin, paraffin; in a given case also a stabilising agent, polyisobutylene, spindle oil and a silicon oil water-repellent agent.

A further characteristic of the bitumen composition according to the invention lies in that the components used change not at all, or to slight extent, the softening point and the needle penetration of the bitumen.

The bitumen composition according to the invention suitable for impregnating (coating) purposes is characterised by the components detailed here-below: weight % bitumen (asphalt) 70-90 linseed oil varnish (boiled linseed oil) 1-3 paraffin 2-10 stearin 3-20 polyisobutylene (Oppanol) (molecular weight 5-10,000) 0-2 silicone resin 0--5 spindle oil 0--4 -naphthol 0.05-0.1 Coating of the cellular polyurethane with open (interconnecting) cells by using the bitumen composition according to the invention is performed in such a manner that at least 2.5, preferably 2.5 to 4, parts by weight of the bitumen composition previously described is applied onto 1 part by weight of the substrate to be coated at a temperature of 60 to 90"C, whereinafter the coated substrate is aircooled in its entire cross-section or simply allowed to cool. For coating purposes, as a substrate we use pre-cut cellular polyurethane strips, which are continuously led between coating rolls having a temperature of 80 to 900C, heated directly or indirectly. The ratio of cellular polyurethane and of the bitumen composition serving for coating may be controlled by adjusting the distance between the coating rolls: The coated cellular polyurethane cooled by air led in counter-current, whereby the flow velocity of the cooling air should be adjusted to different values depending of the length of the cooling area.

The sealing compound, having been coated in a manner described above, can be utilized in several fields of application in the building industry and civil engineering, as example we enumerate some of them: water-tight sealing of expansion gaps; sealing of window and door frames of traditional buildings and in houses made of prefabricated elements; insulation of facing panels and metal; sealing the vertical and horizontal expansion gaps in concrete panels; sealing of expansion gaps of sports structures made of concrete; sealing of expansion gaps in concrete highways and racetracks.

The sealing compound produced in accordance with the invention and coated in the previously described manner does not contain solvents, it is dry to the touch and can be inserted into the gaps by hand or by means of any manual tool (e.g. wooden spatula).

The sealing compound in band form is placed in a compressed state into the gap. After having been inserted the sealing band begins to swell and tries to regain its original form, while due to the exerted force it adheres well to the edges of the gaps and follows the dispiacement in a flexible manner.

The additives (components) admixed to the bitumen do not influence ageing of the cellular polyurethane substrate; use of any solvent can be eliminated; at the same time the appearance of the product and its handling properties may also be improved. In spite of the relatively low softening point of the bitumen, the heat resistance of the sealing compound is satisfactory; under the influence of radiant heat within the temperature range between 95 and 1 000C neither leakage nor outflow of the coating composition could be observed. The sealing compound is absolutely dry to the touch, its sealing and waterproof properties are good, its production requires less energy. Fire and explosion risk do not need to be taken into account, as the flash point of the coating bitumen composition lies over 2500C.

The bitumen component of the composition has a softening point at 46 to 500C (measured by the "Ring-and-Ball" method). Needle penetration at 250C/0.1 mm/71-100, respectively, 55-70, Break point: not more than -1 00C.

The molecular weight of the paraffin used as a modifying agent amounts to 250-450, while the paraffin itself consists to 6095% of normal paraffin hydrocarbon having a pour of at least 52-540C but paraffins with a pour point of at 45-600C may also be used.

The stearin component of the composition is a mixture of stearic acid and palmitic acid.

The linseed oil varnish contains linseed oil siccative, but does not contain either solvent or colophonic acid; specific weight at 200C: 0.935 to 0.950; acid number: not more than 7; saponifying value: 1 89-200; total amount of volatile constituent: not more than 1%; duration of drying: not more than 24 hours. Varnishes generally used as binding materials or thinners in the lacquer- and paintindustry comply with requirements. In order to stabilize linseed oil varnish and stearin against oxidization and to develop fungicidal and insecticidal properties, p-naphthol (melting point: 1 220C) is then added to the composition.

The water-repellent properties of the sealing compound can be increased by using silicone resin.

A silicone resin can be advantageously used which contains heteroalkyl-siloxane as an active ingredient with a dry matter content of 35-38 weight %.

The bitumen composition according to the invention, the application thereof for coating purposes and the improved properties of the sealing compound prepared are described by the way of the following non-limiting Examples: Example 1 82 parts by weight of bitumen (the quality corresponds to the prescriptions of the Hungarian Standard MSZ 3276-76 called "Bitumen SZB 90") are heated at 90-1 000C; then 2 parts by weight of linseed oil varnish (corresponding to the Hungarian Standard MSZ 998-59) are admixed. 10 parts by weight of stearin (corresponding to MSZ 3733) and 6 parts by weight of crude or technically pure mineral oil paraffin (corresponding to MSZ 13245), and at last 0.05 parts by weight of -naphthol are added.The components are mixed under intensive stirring, simultaneously the temperature within the range 90-1 00CC is to be maintained. The physical characteristics of the product are as follows: Softening point 43.50C (MSZ 3253) Viscosity (measured by means of a tar-viscosimeter at 1 1 OOC) 11.8 sec Needle-penetration (250C, 0.1 mm) 69 (MSZ 13162) Example 2 The same procedure as used in Example 1 was followed to prepare the product of the composition described below: parts by weight "Bitumen SZB 90" 73 spindle oil 1 stearin 20 paraffin of technical purity 6 p-naphthol 0.05 The physical properties of the product are the following:: Softening point 44.50C Penetration 160 Viscosity(1100C) 7.2 sec Example 3 The same procedure as used in Example 1 was followed and the product having the composition detailed below was prepared: parts by weight "Bitumen SZB 90" 85.5 linseed oil varnish 2 paraffin of technical purity 6 50% silicone resin 0.5 /3-naphthol 0.05 The physical characteristics of the product are as follows:: Softening point 450C Penetration 93 Viscosity (1100C) 10.5 sec Example 4 2 parts by weight of linseed oil varnish, 0.5 parts by weight of polyisobutylene (Oppanol B10) and 0.5 parts by weight of silicone resin are mixed and homogenized at a temperature between 50 and 70 C. The homogenized mixture is admixed to 86 parts by weight of bitumen (quality SZB 90) having been heated previously to 90-1 000C. While maintaining the temperature, the mixture is homogenized and 5 parts by weight of stearin 0.05 parts by weight of p-naphthol and 6 parts by weight of paraffin are added. Softening point: 450C.

Example 5 The same procedure was used as in Example 1 and a following composition was produced: parts by weight "Bitumen SZB 90" 75.5 linseed oil varnish 2.5 industrial stearin 20 paraffin (technically pure) 2 ,B-naphthol 0.05 Softening point: 44.50C.

Example 6 parts by weight "Bitumen SZB 90" 86 linseed oil varnish 2 stearin 6 paraffin 6 ,B-naphthol 0.05 The physical characteristics of the product are the following: Softening point: 44.50C Penetration 72 Viscosity (1100) 17 sec Example 7 The same procedure was used as in Example 1 and a following composition was produced: parts by weight "Bitumen SZB 90" 82 spindle oil 3 paraffin 10 linseed oil varnish 1 The point of softening of the composition thus obtained is identical to that of the original bitumen, penetration is a slightly higher, viscosity equals to 12-14 sec at 1 1 OOC.

To offer a better survey, in the following table the properties of the bitumen compositions according to the invention are compared to bitumen and bitumen compositions containing certain modifying agents.

Table 1 Viscosity Needle Softening (tar-vis penetration Point cosimeter) Amount of 250C "Ring-Ball" at 1 lOOC Ser. No. Composition the additive 0.1 mm OC sec 1. Bitumen 58 58 46.5 144 2. Bitumen+linseed 2.5 103 40.5 65 oil varnish 3. Composition according 27 160 44.5 7.2 to Example 2 4. Composition according 1 6 72 44.5 1 7 to Example 6 5. Bitumen 70 48 6. Composition according 14.5 93 45 16.5 to Example 3 7. Bitumen 69 46.5 122 8. Bitumen+stearin 8 142 39.5 34 9. Bitumen+paraffin 6 36 47 36 10.Composition according 18 69 43.5 11.8 to Example 1 Example 8 By using the bitumen composition prepared according to the previous examples, coating of the soft cellular polyurethane with open pores is performed as follows: The polyurethane strips to be coated are cut to the desired size, and led between the coating rolls to which the bitumen composition is also charged. The rolls are directly heated and their temperature is maintained between 80 and 90 C. The weight ratio of cellular polyurethane substrate and the coating composition is adjusted to 1:3.5. The coating should be performed continuously and in such a manner that after having passed the coating section of the apparatus the finished sealing compound is led into a cooling tunnel, where it is cooled with air led in counter-current.Intensive cooling and removal of the latent heat from the interior of the sealing compound are accelerated in such a manner that at the beginning, in the middle and at the discharge part of the cooling section cooling air is led in a regulated counter-current, while the heated air is discharged through a chimney. In the cooling section the coated sealing material is processed in such a manner that in its entire cross-section the atmospheric ambient temperature level should be reached, while in order to obtain continuous production, the cooling section and duration of staying within said section is coordinated with the coating period of the product.

The water-absorbing capacity, as well as the water-proof properties of the sealing compound according to the invention have been determined by the following method: Cellular polyurethane strips cut to the same size have been coated in a similar manner with bitumen compositions described in the Examples, taking care that the weight % of the coating composition contained in the cellular material to be coated should be approximately the same. The coated polyurethane strips were subjected to comparative tests, measuring the water-absorbing capacity for one minute and 24 hours.The water-absorbing capacity was measured in weight % in relation to the weight of the sealing compound and calculated on basis of the following formula: weight of the water absorbed during 24 hours-the weight of the water absorbed during 1 minute Water absorption in weight %= the weight of the product In course of the water absorption test the pieces of the size of 100+5 mm have been weighed with an accuracy of 0.01 g.

The non-compressed samples were immersed into a glass tank filled with water in such a manner that the entire volume of the cellular material was covered with water. After 1 minute's immersion the samples were removed without having been compressed, the water adhered on the surface was allowed to run down and the weight of the sample was weighed. The original weight of the sample was designated by A1, the weight after water absorption by A2.

The water absorption over 24 hours has been measured in such a manner that the sample was immersed into the tank filled with water. After 24 hours the sample was carefully removed from the water, the water adhered to the surface was allowed to run down for 1 minute, the sample was weighed and the weight was designated by A3.

The one-minute water absorption can be calculated from the formula given below: A2-A1 x 100=water absorption in weight % A, The 24-hour water absorption can be calculated from the following formula: A3-A2 x 100=water absorption in weight % A, As a control, polyurethane strips with a solvent containing bitumen solution (petrol) have been used. The product coated with the bitumen solution in petrol is indicated by the serial number 1. (Table 2). From the products prepared by the procedure described in the Examples, the impregnated strips according to the Examples 1,3 and 5 have been tested for water absorption. From Table 2 it may be well seen that water absorption of the polyurethane sealing compounds prepared by the procedure according to the invention is considerably less and it is much more waterproof than the polyurethane strips having been impregnated with the traditional bituminous composition.

Table 2 Results of Water Absorption Tests Bitumen content in rela- 1 in. 24-hour Total tion to water water water the sub- absorp- absorp- absorp strate tion tion tion Ser. No. Product weight % weight % weight % weight % 1. Known (coated bitumen 267.1 275 225.9 500.9 solvent) 2. According to 249.7 44.1 59.5 103.6 Example 1 3. According to 268.6 65.5 41.3 106.8 Example 5 4. According to 295 57.8 36 93.8 Example 3 5. According to 318.5 25 17.6 42.6 Example 3

Claims (11)

Claims

1. A bitumen composition for waterproofing purposes, containing bitumen and linseed oil varnish in such quantities that the original viscosity of the bitumen measured by a tar-viscosimeter at 11 00C is reduced to at least 1/5th of its value, and further including stearin, paraffin and optionally a stabilising agent against oxidization, polyisobutylene, spindle oil and a silicone resin as water-repellent agent.

2. A bitumen composition as claimed in claim 1, containing 70-90 weight % of bitumen, 1-3 weight % of linseed oil varnish, 2-10 weight % of paraffin, 3-20 weight % of stearin, 0--2 weight % of polyisobutylene with a molecular weight of 5-10000, 0-5 weight % of silicone resin, 0--4 weight % of spindie oil and 0.05-0.5 weight % of s-naphthol.

3. A bitumen composition as claimed in claim 1, or claim 2, wherein the bitumen component has a softening point in the range between 46 and 500C and a needle penetration 250C; 0.1 mm) in the range of 71-100.

4. A bitumen composition as claimed in any one of the preceding claims, wherein the paraffin component is a technically pure or refined product and the pour-point thereof lies between 45 and 600C.

5. A bitumen composition as claimed in any one of the preceding claims, wherein the stearin component contains a mixture of stearic acid (melting point 55 to 600C) and palmitic acid.

6. A bitumen composition as claimed in any one of the preceding claims, wherein the linseed oil varnish contains linseed oil of a specific weight of 0.935-0.950 (at 200C), an acid number of not more than 7, and a saponifying value in the range of 1 89-200, with the total amount of volatile constituent being at most 1% while duration of drying must not exceed 24 hours.

7. A process for the coating of soft cellular polyurethane substrate with open pores, comprising applying at least 2.5 parts of the bitumen composition as claimed in any one of the preceding claims at a temperature between 60 and 900C, onto 1 part of the substrate to be impregnated, and cooling the coated substrate coated with air or allowing it to cool.

8. A process as claimed in claim 7, wherein the pre-cut cellular polyurethane strips serving as substrate to be coated are led between rolls heated to the temperature of 80-900C and the coating composition is also charged continuously there, while the ratio of the bitumen composition in relation to the cellular polyurethane is controlled by adjusting the distance between said coating rolls.

9. A bitumen composition as claimed in claim 1, substantially as hereinbefore described in any one of the Examples.

10. A process for coating a polyurethane substrate as claimed in claim 7 substantially as hereinbefore described in Example 8.

11. A polyurethane substrate when coated by a process as claimed in any one of claims 7, 8 or 10.