CH464415A - Adhesive solution or paint-like mass - Google Patents

Description

       

      Adhesive solution or lacquer-like mass When applying adhesive solutions or lacquer-like masses to surfaces, edges or laths, the fact that it is difficult to estimate the amount of application required if the adhesive solution or the lacquer and the substrate are similar in color or due to their transparency is difficult. Particularly great difficulties arise with application methods such as B. when spraying, where the amount applied per unit area depends on the time, a nozzle opening or the pressure.

   Furthermore, wherever the amount applied is difficult to see due to poor exposure conditions, such as B. grate on a slat attached to a ceiling.



  In the case of adhesives, coloring has the disadvantage that visible glue joints unintentionally emerge due to their inherent color and that unwanted color effects arise in the case of a lacquer. Also, colored glue can show through with thin materials.



  The invention now forms an adhesive material solution or a paint-like mass that contains a clearly visible dye when applied to the substrate, which takes on a new, less intense color or loses its color when drying due to pH change. The pH change can e.g. B. be caused by the action of humidity, carbonic acid or oxygen. The dye can take on a color that matches the substrate so that it no longer interferes with visible joints.

   The color change can also be achieved by adding a volatile acid or base, after the evaporation of which a pH change brings about the desired color change.



  In the following examples, a 20% polychloroprene solution in methyl ethyl ketone: toluene: gasoline = 1: 1: 1 is used, which contains 5% MgO based on polychloroprene. Of course, the examples can also be applied to lacquers or lacquer-like compositions. <I> Example 1 </I> 100 parts of polychloroprene solution, as described above, are mixed with 2 parts of 0.4% strength bromothymol blue solution.



  When spraying in air with at least 30% relative humidity, the mass on the surface turns purple and changes gradually from green to yellow in the air. If 0.3% oxalic acid is added, instead of the violet coloration, an intense blue coloration occurs, which also disappears via green to yellow.



  <I> Example 2 </I> 100 parts of polychloroprene solution, as described above 0.4 parts of oxalic acid 2.0 parts of bromothymol blue 0.4% in MEK The adhesive has a yellow-green color, when it is sprayed it hits the surface with an intense green-blue, changes to green within an hour in the air and is light yellow the next day.



  <I> Example 3 </I> 500 parts of the above polychloroprene solution 10 parts phenolphthalein 1% in MEK 10 parts ethylamine 70% in water When this adhesive is sprayed in air with at least 50% relative humidity, the adhesive on the base hits an intense red and changes to colorless within 10 minutes.



  <I> Example 4 </I> 450 parts of the above polychloroprene solution 9 parts phenolphthalein 1% in MEK 2 parts water glass solution 40 B6 The water glass must be stirred in with a high speed stirrer, otherwise the dye will not be evenly distributed. When sprayed, this adhesive appears rose-red and changes to a very faint pink within a few days. <I> Example 5 </I> As for example no. 4. Instead of water glass, however, ammonia gas is passed into the solution until it turns blue-green.

   The ammonia gas can also be introduced separately into one of the solvents used.



  <I> Example 6 </I> 100 parts of polychloroprene solution 2 parts of bromothymol blue 1% in MEK 0.5 parts of NaOH 25% in water 3.5 parts of benzoic acid 15% in MEK After spraying or spreading with a spatula or brush the applied solution is blue-green. The color disappears in the air after about 10 minutes.



  In order to obtain an intense color, it is necessary that it is soluble in the solvents. If acids or bases are used, solubility in the solvents used must also be required of these additives, or the additives which are immiscible with the solvents must then be emulsified, advantageously using an emulsifying agent.


    

Claims (1)

PATENT CLAIM Adhesive solution or lacquer-like mass, characterized in that it contains a dye which makes it clearly visible when it is applied to the substrate, which takes on a new, less intense color or loses its color when it dries due to a change in pH. SUBClaims 1. Adhesive solution or lacquer-like mass according to claim, characterized in that it contains volatile bases or acids. 2. Adhesive solution .or paint-like mass according to claim, characterized in that the dye reacts against a change in pH that comes about .by the action of air-carbonic acid. 3. Adhesive solution or paint-like mass according to claim, characterized in that the dye has a transition zone which is between a pH of 3-10. 4. Adhesive solution or lacquer-like mass according to claim, characterized in that it contains bromothymol blue, phenolphthalein in colored form, bromophenol plaque, bromocresol green., Methyl red, bromophenol red, phenol red as the dye. 5. Adhesive solution or paint-like mass according to claim, characterized in that it is a vüässrige solution.