DE1494008A1 - Process for the antistatic finishing of high molecular weight compounds - Google Patents

Description

Process for the antistatic treatment of high molecular weight compounds It is known that moldings of any kind made from high molecular weight substances become more electrostatic Tend to charge. Due to this electrostatic charge, the moldings show im practical use after a short time dust deposits on their surface, the generally known shape of crow's feet or zigzag pattern when the battery is heavily charged demonstrate. In addition, due to strong electrostatic charge, it can be caused by the large Potential difference lead to sparking.

In the case of fibers or fabrics, the static charge manifests itself through quick and heavy pollution. Because of these disadvantages of static electricity the use of such polymers can be called into question.

There are numerous known methods by which the electrostatic Charging should be prevented or at least reduced. For example, it has been for a long time known to condition moldings after their production, i.e. the moist ones To expose to air. Moldings or fibers to be given an antistatic finish, e.g. such those made of polyamide, cellulose acetate or viscose absorb a certain amount of water on, whereby the electrical conductivity is greatly increased. Apart from this, that some plastics, such as. B. polyolefin, absorb practically no water and an antistatic preparation for moldings made of this material in such a way Way is not possible, this method also shows the disadvantage that the water content the plastic objects are reversible, d. H. treated in this way during storage Parts in a dry atmosphere lose their antistatic effect.

As it is used to achieve an antistatic effect in most Cases of insufficient exposure to humid air became various Processes developed in which the plastic or the surface of it is manufactured th moldings with the help of antistatic agents is changed so that static electricity is prevented.

A number of substances have been proposed for this purpose. These Compounds can be classified into the following 5 groups: 1. Nitrogen-containing Compounds such as amines, amides and quaternary ammonium salts of e.g. urea derivatives.

2. Sulphonic acids and aryl alkyl sulphonate.

3. Phosphoric acids, aryl-alkyl phosphates and phosphoric ester amides.

4. Polyglycols and their derivatives including polyglycol esters of Fatty acids they are polyglycol-aryl-alkyl-ethers.

5. Polymers of polyhydric alcohols and their derivatives.

The antistatic substances can affect the plastic molding can be applied by treatment with a solution of the products. But you can can also be incorporated by mixing the appropriate preparations into the plastic powder before processing.

Also the incorporation of highly hygroscopic inorganic salts is already known, but siv becomes common because of the connected with Danger of corrosion for the processing machines rejected.

The subsequent treatment of plastic moldings with antistatic effective solutions has serious disadvantages: the antistatic effect is mostly depending on the water vapor content of the air. The adhesive strength of the subsequently applied Substances is inadequate in the previously known antistatic agents, so that their effect due to abrasion and daily use is only of limited duration. Farther there is a risk of changing the surface of the material. Some of the to be raised Antistatic substances are extremely hygroscopic, making them unnecessary attract a lot of water. In addition, they are usually not physiologically harmless.

An antistatic preparation by incorporating the antistatic agents has the advantage that it is possible at any time to search for high molecular weight substances To add an antistatic finish to the polymerisation on request. In general you need to Achieving a sufficiently large antistatic effect the already known incorporable Organic substances can be added in amounts that change the characteristic properties of the substances, such as a reduction in the for the processing of suitable temperature ranges, hardness, rigidity, heat resistance, result in deterioration in color, etc. Often it is to substances, through their incorporation of the high molecular weight Substance loses its physiological harmlessness. Really effective, technical useful antistatic agents for incorporation into plastics are not yet available known.

Another possibility to make high-molecular substances antistatic, consists in incorporating additives during the polymerization. This method has the disadvantage that the high molecular weight substance is already antistatic during its manufacture is equipped, while often only shortly before the final deformation by the Processor can decide whether a antistatic equipment is required.

By adding the previously known additives during the polymerization are also in many cases the characteristic properties of the Substances such as Water absorption, chemical resistance, toughness and hardness, changed.

It has now been found that organic high molecular weight compounds can advantageously be given an antistatic finish with urea derivatives by using substituted ureas or thioureas of the general formula as antistatic compounds which are incorporated into the high molecular weight compounds used, where X = 0 or S, R1 = -H or -CH3, R2 = alkyl (with 12 to 20 carbon atoms), R3 = H and R4 -H, alkyl (with 1 to 20 carbon atoms), aryl -, cycloalkyl or alkylaryl groups and can also be substituted by amino groups, oxy groups, alkoxy groups or carboxyalkyl groups.

Also, compounds that have several good anti static efficacy contain substituted urea or thiourea groups in the molecule, e.g. by an alkylene radical linked together.

The antistatic agents are advantageously the plastics in one Concentration of 0.1 to 7% by weight and preferably 0.4% by weight added. Ureas and thioureas, respectively, generally have the best intistatic effect when R1 is a methyl group and R2 is a longer alkyl radical such as z.fl. the stearyl or Mean dodecyl radical.

Suitable antistatic substances include, for example, the following Compounds can be used without limiting the method to these compounds should be: N, N-methylstearylurea, N, N'-didodecylurea, N, N-methylstearylthiourea.

The use of urea and thiourea for subsequent Antistatic finishing of finished fibers and threads by spraying on solutions or aqueous dispersions is already in the German patent application B 14 905 described.

However, these unsubstituted ureas are not suitable for incorporation in plastics, as their effect is lost during processing. Probably decomposition occurs during thermoplastic deformation as a result of the high temperatures of connections. This is also supported by the strong appearance during processing Discoloration.

It is an advantage of the present application that an entire class of compounds is described as antistatic agents, so that from the large number of effective products Depending on the needs, compounds specifically for a particular Plastic or a particular field of application are suitable, can be selected. Connections can be selected according to the special wishes of the processor be that as a result their solubility in water or organic Solvents or in the plastic itself, their color, decomposition or melting or Boiling temperature etc. result in end products with optimal properties. In many Cases it can also be advantageous to use mixtures of 2 or more of the described Connections to use.

Even by adding small amounts of the substances mentioned to plastics an antistatic effect is achieved, so that mixtures produced from such mixtures Briquettes do not become superficially charged and have no tendency to attract Show dust. The mechanical and thermal properties, the thermal stability and the color and transparency of the polymers are improved by adding the above Substances practically unchanged.

The processing conditions and the temperature range in which the plastics deform thermoplastically remain the same. Farther the products are compatible with all polymers. The achievable antistatic The effect is independent of the humidity of the environment and is practically unrestricted Duration. Exudation is not observed. The surface is also not hygroscopic, but remains unchanged.

By adding substances of the specified class, reward all high-molecular substances that are due to their electrostatic charge tend to be polluted by the attraction of dust. A particularly good effectiveness show these compounds e.g. in polystyrene and in copolymers of styrene with butadiene, acrylonitrile and / or vinyl carbazole, in polyvinyl chloride and vinyl chloride copolymers, Polyterephthalates, polyolefins, such as the polymers and copolymers of ethylene, Propylene, butene (1), pentene (1), 4-methylpentene (1), hexene (1), 5,5-dimethylhexene (1), Octadecene (1), 4-phenylbutene (1) and vinylcyclohexene, polycarbonates, polyformaldehydes, Polyacrylonitrile, polyacrylic acid esters, polymethacrylic acid esters, polyamides, polyurethanes, Polyvinyl esters, polyacetals, polymers of fluoroolefins, cellulose derivatives and Polymer blends containing the above polymers. Also unsaturated polyesters and base cured epoxy resins as well as paint raw materials can before or during their processing by adding the aforementioned antistatic agents equip it with antistatic properties without difficulty.

The substituted ureas or thioureas can be before or during the polymerization, as well as later the powdery high polymer as can also be added to the granules. Depending on the nature of the plastics, this may interfere in the melt, in solution or by drawing up adi the powdery or granulated High polymers take place. It is best done before or during processing. It has shown. that the type of training is not very important.

On the other hand, it is important that the substances acting as antistatic agents are distributed as well as possible in the plastic.

Those with the compounds described antistatic High polymers can be processed by all customary processing methods, e.g. on presses, Injection molding machines or extruders. It can accordingly be used for pressing or injection molded bodies, semi-finished products, foils, blown hollow bodies, pipes, fibers, threads, Making monofilaments, etc. The resins mixed with the compounds mentioned can be used as paint or

Casting resins or in combination with glass fibers and / or fillers processed in the usual way.

The high polymers finished in this way are particularly interesting for packaging purposes (packaging, canisters, bottles, cups), vacuum cleaner accessories, Conveyor belts, exhibits and models, housing parts (e.g. for radio and Televisions, vacuum cleaners) electrical systems such as lighting fixtures, cable insulation, Plugs, switches or fittings, air conditioning and lighting systems, plastic dishes, kitchen machines, Threads, fibers, fabrics, foils, lacquers, i.e. wherever on the antistatic Equipment is valued, The antistatic effect of inorganic or organic substances in high molecular weight substances can be easiest determine by means of cigarette ash. Injection molding, extruder or Press plates with a woolen cloth strong approx.

15 ec. rubbed and rubbed about 2mm over a layer of cigarette ash held. If the plastic sheets have good antistatic effectiveness, there will be no Cigarette ash attracted. It should be noted that the cigarette ash is always is fresh and finely powdered. It must not be older than approx. 6 hours.

There are a number of other methods for determining the electrostatic Charge known, but it has been found that only the test method listed is genuine, delivers practical values.

Table 1 shows the results of the investigation. It can be seen that with all of the substances listed, an excellent one antistatic effect can be achieved.

Examples Some antistatic compounds similar to those described in the Molecular formula explained in the description have been converted into various high polymers Fabrics incorporated. A compilation of the antistatic agents used and the added ones Quantity and the test results are given in Table 1.

The incorporation of the antistatic agents was carried out in the following way: Examples 1, 2, 3, 5, 7, 8, 10, 11 and 12s On 10 kg of the plastic granulates mentioned the specified amounts of the antistatic agents were determined by the dry coloring process raised as a powder. A so-called "roll barrel" was used as a device for pulling it up. That Material treated in this way was then extruded, granulated and made into 1mm thick Splashed plates.

Example 4t 200 g of a commercially available unsaturated polyester resin, that by condensation of 5 moles of ethylene glycol with 3 moles of maleic anhydride and 2 moles of phthalic anhydride and then dissolving the condensation product in 30 wt .-% styrene had been obtained, after the addition of 2% methyl ethyl ketone peroxide, 0.1% cobalt naphthenate and 1.0% N, N-methylstearylthiourea cast into sheets and cured at room temperature in the absence of air.

Example 6s 10 kg of isotactic polypropylene were placed in a hischer with 1 kg of a hot show acetone solution of J, N-methylstearyl-N'-methylstearyl-N'-benzylurea mixed. After the solvent had evaporated at 75 ° C., granulation took place and then processing the material into injection molded sheets.

Example 9s 10 kg of isotactic polypropylene were added to a mixer with 1 kg of a hot 5% acetone solution of N, N-methyl-stearyl-N'-o-methoxy-benzylurea mixed. After the solvent had evaporated at 75 ° C., granulation took place and then processing the material into injection molded sheets.

Tabel When using antistatics structure standard 1 IZuatB Ac- apiel plastic P, ansi- unLt i 1 'polystyrene H, W-nethy-; c.18H37 NH2 CH 2 acrylonitrile methyl stearyl CH3 styrene-mis-urea N polymer 0 = CCH 0.75 ~ 18 C18H37 37 NH2 3 High Pressure N'-Dioteartl- / NH-C18H37 polyethylene urea 0 = ~ C 18H 4 polyester- methylstearyl- CH, resin casting thiourea H or lacquer- S = C 18 37 coating NH2 5 low pressure N, N-methyl-CH3 Polyethylene stearyl-N'-N ~ H ethylamino- ~ 0 = C 18 37.5 urea NH-C2Ht 3 4. j2 6 polypropylene N, N-methyl- N <CH3 stearyl-N'- H benzyl urine-O = C 18 37 0.5 substance NH-CH2 < 7 butadiene-N, N'-didodecyl-NH C12H25 mixed styrene urea 0 = C \ 4 polymer NH C12H25 8 low pressure N, N-methyl, CH7 polyethylene stearyl-N'-, N ethylamino- 0 = CCH 15 urea 18 37 NH2-C2H4-NH 9 polypropylene N, N-methyl- CH, dodecyl-o- / CH methoxy-benzyl-O = C 12 25 0.5 urea \ NH-CH2 OCH3 When using antistatic agents ß structural formula add anchoring :; i1: 1 Antistatic additive structural formula used r. plastic 10 butadiene-N-aoetyl-N> s tyrolei ech- dodecyl-urine- polymer fabric * aINHlc H 12 23 CH3 11 low pressure- I, nefhyl- / polyether taryl-N'- 8H37 2, r 12 high pressure N, N-methyl-H3 polyethylene stearyl-N - cyclohe 09CC18H 3 urea 37 NH-o

Claims (4)

Claims 1. A process for the antistatic treatment of organic high molecular weight compounds with urea derivatives, characterized in that one alb antistatic compounds which are incorporated into the high molecular weight compounds, substituted ureas or thioureas of the general formula used, where X = 0 or S, R1 = -H or -CH3 'R2 = alkyl (with 12 to 20 carbon atoms), R3 = dog R4 -H, alkyl (with 1 to 20 carbon atoms), * aryl -, cycloalkyl or alkylaryl groups and can also be substituted by amino groups, oxy groups, alkoxy groups or carboxyalkyl groups. 2. The method according to claim 1, characterized in that as an antistatic N-methyl-N-stearyl urea is used. 3. The method according to claim 1 and 2, characterized in that one 0.1 to 7% by weight, preferably 0.5 to 4% by weight, of the antistatic substance used. 4. Verfahrennach claim 1 to 3, characterized in that one used as antistatic agents mixtures of the antistatic compounds.