DE1117867B - Aqueous polypropylene dispersion - Google Patents

Description

The aqueous polypropylene dispersion according to the invention for coating or impregnating porous and non-porous materials, especially paper, cables, ropes, textile products, metals, asbestos and the like, contains 50 to 95 percent by weight of crystalline polypropylene and optionally dispersants or emulsifiers.

The aqueous polypropylene dispersion according to the invention can be produced in any desired manner. For example you can use divided polypropylene with a content of 50 to 95 percent by weight crystalline polymer, the particles of which have a size of 0.1 to 20 μ, in the presence or absence of dispersants or emulsifiers in water. In contrast to other polymers Such a divided polypropylene can be made into substances directly by polymerizing the monomer to win. If polypropylene with a particle size of over 20 μ is available, you can reduce the particle size by grinding, for example in a roller mill, preferably using heat and in the presence of oily materials or other non-solvent modifiers.

As an alternative to marriage one can use procedure apply in which the polymer is dissolved in a solvent before putting it in the water dispersed. A convenient method of this type is that of a solution of polypropylene in an organic solvent that is not or only slightly miscible with water, whereupon the solution is emulsified in water and the solvent is removed by evaporation. To Another method is to prepare a solution in a water-miscible organic solvent produced, the polypropylene precipitates by adding water and removing the solvent through Evaporate.

In all processes, the production and stability of the aqueous dispersion are determined by the presence of dispersants or emulsifiers contained in the water or in the polymer or are formed when the components are mixed (for example in the presence of saponifiable Oils in the polymer and sodium hydroxide in the water). The dispersion can with the help are stabilized by protective colloids in the usual way.

The dispersions of the invention are more diverse for coating or impregnating porous and non-porous materials, for example paper, cables, ropes, yarns, textile products.

Aqueous polypropylene dispersion

Applicant:

Montecatini Soc. Gen. per l'Industria
Mineraria e Chimica, Milan (Italy),

and Dr. Dr. eh Karl Ziegler,
Mülheim / Ruhr, Kaiser-Wilhelm-Platz 1

Representative: Dr.-Ing. A. v. Kreisler,

Dr.-Ing. K. Schönwald,

Dipl.-Chem. Dr. phil. H. Siebeneicher

and Dr.-Ing. Th. Meyer, patent attorneys,

Grain 1, Deichmannhaus

Claimed priority:
Italy of October 9, 1956 (No. 14 826)

Achille Bosoni, Milan (Italy),
has been named as the inventor

Metals (e.g. wires, plates and foils) and asbestos. Through such treatment can the materials are given some of the properties of polypropylene, such as its impermeability for gases and water, its chemical resistance, its corrosion resistance and brightness, or you can change or improve their properties, for example the crease resistance of fabrics or give them new useful properties, for example the ability to be welded with itself or with other materials, for example paper on paper or metal on tissue.

Protective coatings are formed with the aid of the dispersion according to the invention by application with a squeegee, roller or brush, or by spraying or dipping. The coating can be achieved by applying mechanical pressure with the aid of pressure plates or other suitable Devices using temperatures above the softening point of the polymer (according to

109 740/581

the drying of the dispersion, preferably at temperatures a little below 100 ° C) solidify and equalize. The main amount of the present dispersant, which has the mechanical and chemical Could reduce the resistance of the coating, can be done by immersing the finished Remove the object in warm water.

Porous materials such as asbestos and cork can be transformed into solid materials by impregnation that can be deformed into bodies with completely new properties.

The dispersions give very good results as laminate adhesives, for example for layered ones Layers of absorbent materials such as textile fibers. After the union of the individual layers with the dispersions in between, the whole is dried out and at the same time or preferably then under mechanical pressure to temperatures above the softening temperature heated by polypropylene.

Finally, there is also the possibility of producing threads, films and other profile articles Expressing the dispersion through a suitable opening into a coagulation bath mentioned.

Polypropylene can be produced with a very high molecular weight exceeding 800,000. It unites properties in a unique way that are also found individually in other thermoplastic materials Resins occur. It is Z. B. transparent, flexible, light, gas and water impermeable, non-toxic, odorless and heat-resistant. It can be welded and coated with transparent or opaque dyes to be colored. In some properties, e.g. B. its heat resistance and gas impermeability, it is superior to all other thermoplastic materials.

A dispersion according to the invention can be produced quickly and economically. she can be prepared in a very concentrated form, which reduces shipping and storage costs and subsequently diluted. The previously known and proposed methods for The production of concentrated resin dispersions does not result in concentrations of more than 50 percent by weight, even where the dispersion is obtained in the form of a paste. Leave with polypropylene significantly higher concentrations can be achieved, which can reach 95%.

The properties of the aqueous dispersions according to the invention can be determined by adding Modifiers such as fillers, pigments and Plasticizers, modify. The addition can be made to the finished dispersion or at any time take place during their manufacture.

In the following examples, all information on ratios relate to weight ratios.

example 1

30 parts of water and 10 parts of a 12% strength aqueous ammonium polymethacrylate solution are placed in a horizontal mixer and 100 parts of polypropylene powder (molecular weight 90,000) in the form in which it is obtained directly from the polymerization. The paste obtained after 30 minutes of mixing is made through a disk mill similar to that for varnishes used type led. Mixing and charging of the mill can be done continuously.

A stable, homogeneous paste is obtained which immediately provides a good polymer dispersion when it is used diluted with water for use.

Example 2

Bring 100 parts of granular polypropylene (molecular weight 100,000) in a steam-heated Roller mill in a plastic state and mixed with 10 parts of oleic acid. Mixing is taking Cooling and rolling continued. The pasty mass is weakly divided to form a fine powder. 10 parts of a condensation product of ethyl alcohol (1 mol) and ethylene oxide are mixed (17 mol) and 100 parts of water with this powder and finally adds 10 parts of a 12% aqueous Ammonium methacrylate solution too.

A stable dispersion is obtained in the form of a paste, the dispersed particles of which have a medium one Have a diameter of 10 μ.

Example 3

200 parts of coarse polypropylene powder (molecular weight 150,000), 25 parts of stearic acid, 6 parts of the condensation product of cetyl alcohol (1 mol) and ethylene oxide (4 mol) as well 2000 parts of trichlorethylene and heated under reflux to 70 to 80 ° C until the polymer is complete is resolved.

A solution of 5.5 parts of potassium hydroxide, heated to 80 ° C., is poured into the warm solution while stirring in 1500 parts of water. The trichlorethylene is removed from the emulsion thus obtained Distillation at 70 ° C under a pressure of 735 mm Hg. The distillate is continuously through a working separator while the water returns to the bladder.

After the trichlorethylene has been distilled off, the residue is a stable aqueous dispersion of Polypropylene is. The mean diameter of the particles is 5 μ.

Example 4

A powdered polypropylene (molecular weight 90,000) is in the form as it is directly in the Polymerization occurs, subject to venting to remove the coarser parts from the finer parts separate. 10 parts of this finely divided polypropylene are mixed with 2 parts of water and then passed through a disk mill of the type used for varnishes. A homogeneous paste is obtained, which immediately provides a polymer dispersion that is stable for 4 to 5 hours when you use it Water diluted.

Claims (5)

Patent claims: 1. Aqueous polypropylene dispersion for coating or impregnating porous and not containing porous materials, in particular paper, cables, ropes, textile products, metals and asbestos 50 to 95 percent by weight of crystalline polypropylene and optionally dispersants or emulsifiers. 2. Dispersion according to claim 1, containing 1 to 10 percent by weight, based on the polypropylene, a dispersant or emulsifier. 5 6 3. Dispersion according to claim 1 and 2, enthal- characterized in that first the tend to dissolve the polypropylene in a solvent in a particle size equal to that of polypropylene 0.1 to 20μ. Solution is emulsified in water and the solution 4. Dispersion according to claims 1 and 2, containing medium removed by evaporation. tend a previous in the presence or absence of 5 oily substances up to a particle size of 0.1 to 20 μ ground polypropylene. ¹ ^ publications considered: 5. Process for the preparation of aqueous Belgian patents Nos. 508 835, 511115;
Polypropylene dispersions according to Claim 1, Canadian Patent No. 464,489. 109 740/581 11.61