DE2540521A1 - MOLDED BODY MADE OF AETHYLENE COPOLYMERISATE WITH REDUCED SURFACE STICKNESS AND METHOD OF MANUFACTURING - Google Patents

Description

■ f "D \ £ Patent attorneys:

IEDTKE - DÜHLING "! \ INNE DipWng. Tiedtke

Dipl.-Chem. BQhling Dipl.-Ing. Chins

8 Munich 2, P.O. Box 202403 O Q / Π £ \ J 1 Bavariarlng 4

.. (ο 89) 53 96 53 - 56 Telex: 5 24845 tipat cable: Germaniapatent Munich

September 11, 1975 B 6810

Imperial Chemical Industries Limited London, UK

Molded body made of Ethyleh copolymer with reduced Surface stickiness and method of Manufacturing. .

The present invention relates to molded articles, in particular in the form of granules made from an ethylene copolymer, the surfaces of which have reduced stickiness. The invention also relates to a method for producing such shaped bodies.

Copolymers of ethylene with an unsaturated fatty acid ester, such as alkyl acrylates or alkyl methacrylates, especially with vinyl acetate, become increasingly sticky when the ester content of the copolymer increases, for example from 28 % to 55 % of the weight of the copolymer. the

Stickiness causes adjacent surfaces to stick together / 8 609814/1193

Deutsche Bank (Munich) Account 51/61070 Dresdner Bank. (Munich) Account 3939844 Postscheck (Munich) Account 670-43-804

_ ₂ . ■ '2640521

be liable; especially when such molded bodies are in the form of granules made from a copolymer of ethylene and vinyl acetate are present, then the individual granulate particles stick to one another . and form large agglomerates, which impairs the pourability of the granulate. ■ ·

It has already been suggested to overcome this those associated with the tackiness of ethylene copolymers Difficulties the copolymer surfaces with powdery inert minerals such as talc, silicon dioxide or clay, or with wax, like ebva with powder)! Paraffin wax, or in powder form !! Dusting Fischer-Tropsch wax. Dusting with powdered minerals ensures that the granulate can be poured at the same time however, with the subsequent further processing of the granulate, for example in a melting process, mineral Impurities introduced into the copolymer. Dusting with the powdery waxes also ensures that Pourability of the granulate; the dusted granules however (just like other copolymers whose surfaces have been dusted with wax) decreased Lxchtdurchlässigkext, usually such dusted granulate particles appear in comparison with non-dusted ones Particle opaque. In addition, dusting with wax leads to the introduction of impurities into the copolyraerisate on the occasion of the subsequent further processing, for example in a melting process, whereby the solidified again

Copolymer gets a cloudy appearance.

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■ The object of the present invention is to provide the indicated Disadvantages in reducing the tackiness of surfaces made of ethylene copolymer to reduce or completely to eliminate. .

The invention thus relates to molded bodies, in particular in the form of granules, which essentially consist of a copolymer consist of ethylene and an unsaturated fatty acid ester, with an agent on the surface of the molded body is applied, which reduces the stickiness of the surface. In particular, the moldings according to the invention can be in the form of granules or in the form of a film made of the ethylene copolymer mentioned, in which case the moldings consist entirely of the ethylene copolymer.

Examples of unsaturated esters include the methyl, ethyl and tertiary butyl esters of acrylic or methacrylic acids. The. Invention is particularly valuable for ethylene copolymers, the more than 18, in particular 28 to 45 wt.? Contain vinyl acetate or other esters.

In the "Encyclopedia of Chemical Technology" by R. E. Kirk and D. F. Othmer (Interscience-Publisher), vol of the 2nd edition, on pages 507 to 593 there is an overview of means for surface treatment. According to the invention are preferred either anionic or nonionic Surface treatment agents are used, with soaps and polyoxyethylene compounds being particularly preferred.

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The soaps are compounds of the following general formula

0.

R - C - Ο ^θ Μ ^φ

where R is an alkyl radical having 8 to 22 carbon atoms and M means an alkali metal ion or an ammonium ion. A metal soap preferred according to the invention is potassium oleate. The for the use as a surface treatment agent according to the invention preferred polyoxyethylene compounds are condensation products of ethylene oxide with alkylphenols, the alkyl radical 7 to 1.3 carbon atoms, contains, or is Condensation products of ethylene oxide with primary aliphatic alcohols with 11 to 19, in particular with 12 to 16 carbon atoms. According to the invention, those condensation products are preferred which are used in the. Condensation of 3 to 7 moles of ethylene oxide for every 1 mole of phenol or alcohol. The polyoxyethylene compounds are 'non-ionic Surface treatment agents, however, they can easily be anionic Surface treatment agents are transferred by allowing sulfur trioxide to act on these compounds, so that the corresponding sulfates are formed. The sulfates can be in the form of the alkali metal salts or in the form of the Ammonium salts are present, the ammonium salts being preferred according to the invention.

The surfaces of the ethylene copolymers can be coated with the surface treatment agent in the usual way be, for which the surface in a dispersion (preferred

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'2 5 A O 5 21

■ - 5 -

in the form of an aqueous solution) of the surface treatment agent. The moldings according to the invention are frequently in the form of granules, as obtained after extruding the copolymer through a nozzle and then chopping the extrudate strand using a knife. The extrusion can be done through a nozzle into a water bath and the chopping can be done under the surface of the water, as described, for example, in British Patent 774,681. In such a case, the coating of the shaped bodies, ie the granulate particles, can expediently take place in such a way that the surface treatment agent is added to the water bath in which the knife works. Overall, such a cutting device consists of a water bath, an extruder, a nozzle through which the copolymer is extruded directly into the water bath, and rotating knives working under water, which are arranged in such a way that they feed the molten material Cut granulate particles when they come into contact with the water in the water bath. The aqueous solution preferably contains .0,05 to 1 wt -.% Surface treating agent and copolymers of ethylene and "vinyl acetate is preferably used a solution containing 0.1 to 0.5 wt .- $ Oberflächenbehändlungsmittel contains.

If the surface treatment agent is added to the water bath with the underwater cutting device described above added, it is often advisable to add a foam-preventing agent to the water.

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set. Such additives suppressing foam formation are, for example, nonahol, dirnethylsilicone, sorbitan monolaureate, Amyl acetate or oleic acid, these additives expediently to the water in amounts from 0.001 to 1, preferably in amounts from 0.005 to 0.3 wt. can be added. To others, too Foam-suppressing additives that can be used in conjunction with water include propylene glycol and triethanolamine and dioctyl phthalates. These and other anti-foaming agents are in the "Encyclopedia of Chemical Technology", by R. E. Kirk and D. F. Othmer, Volume 9 of the 2nd edition, on pages 898 to 900. Even in the case of which, in addition to the surface treatment agent, is used to prevent foaming Granulate particles with good rubble and flow properties are obtained.

In those areas where the water used for the production process has a high proportion of mineral Has hardness, the aqueous solution can additionally contain a complexing agent such as; the potassium salt of ethylenediaminetetraacetic acid can be added to prevent the formation of foam or other deposits which could impair the transparency of the copolymer. Alternatively, small amounts of alkali (e.g. as an aqueous ammonia solution) are added.

The following examples serve to illustrate the invention without restricting it,

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example 1

Of a copolymer of 60 parts ethylene and HQ JS wt -.% Vinyl acetate with a melt of ELießindex. 50 g / 10 min, granules were produced in the form of flattened spheres. Six different tests were carried out on these samples, for which purpose the granules were immersed in an aqueous solution which was Ό, Η by weight ί of one of the The following table I contained agents for surface treatment.

Table I.

Various suitable surface treatment agents Test surface treatment agents Art

1 potassium oleate - anionic

2 · Sulphate of the condensation product of 3 moles of ethylene oxide with 1 mole each a mixture of 67% by weight of tridecanol and 33% by weight of JS. Pentadecanol anionic

3 Common ones for household use

liquid soap. anionic

U Condensation product from nonylphenol

and ethylene oxide non-ionic

5 Dimethyl silicone non-ionic

6 disodium salt of a condensation product

from methylene sulfonic acid with formaldehyde anionic

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• After the granules come back from the the surface treatment agent containing aqueous solution was taken out, it was allowed to dry, leaving a coating of surface treatment agent remained on the surfaces of the granules.

The coated samples turned into a handful Granules taken; warmed in the hand, - being in each After heating, the granulate particles fall freely flowing, i.e. remained pourable and showed little tendency to adhere to one another. In addition, the overdrawn showed Granular particles versus those particles that are immersed in water that did not contain any surface treating agent showed very little loss of clarity. - ·

Among the six attempts listed, that seemed product obtained after experiment .1 has the best pourability ·. ·

Example 2.. '

In each case 100 ml samples of the aqueous solutions used in the individual experiments of Example 1 were Filled into identical bottles that can be closed with a screw cap and shaken 10 times each time to get the To simulate conditions which lead to the formation of foam in the underwater cutting device. To the shaking the bottles were put upright and the

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Height of the foam measured above the liquid level, this foam height as a guide to the level that has occurred Foaming was considered. The results of these measurements are shown in Table 2 below.

Of the aqueous solutions used in the respective experiments of the example, one further was in each case 100 ml · sample taken and filled into identical bottles, which can be closed with a screw cap, and also different ones Amounts of various agents for suppressing foam formation were added, which are listed in Table 2 below are named in detail. Here, the amounts of added agent for suppressing foam formation correspond to the Specifications in weight? As stated above, the bottles were used 10 times shaken and then placed upright. Again, the height of the foam formed was above the liquid level measured; the measurement results are listed in Table 2 below.

In all cases immersion of the granules resulted from the copolymer of ethylene and vinyl acetate into the various aqueous solutions according to Example 1, which also has a means of suppressing foam formation contained, to form free-flowing granulate particles.

As can be seen from the test results in Table 2, the solution from test 6 resulted in the lowest

Tendency to foam.

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Table 2

Effect of adding a foam suppressing agent

-JO
CO

j attempt used Mean and amount of the 0.01 %
Dimethyl
silicon Foam (cm) across the liquid level 0.1 %
Oleic acid » ⁵ no 0.1 '2
Nonanol 2.0. I ο ι t
ι sorbitan
¹ monolaureate 0.1 %
Amyl acetate 1 , 0. : ■ 1 3.0 2.0 1.5 \ ■ 2.5. 3.0
■ 2 5 ; 2 1.0 3.0 7.0 ! ■ i, o 1.0 , 5 ! ■ 3 7.0 2.0 2.0 ^; , 4.5, 7.0 1 , 3 I.
! 4th
I. 2.0 0.5 '' - 1.5 '".3.5 <° , 3 I.
; 5 0.5 0.3 ; 0.5 ', <0.3 ■ 0.5 . <° ! ^6th
i <0.3 i 0.5 1.0 <0.3

Claims (4)

Claims 1. Shaped bodies, in particular in the form of granules, essentially composed of a copolymer of ethylene and a consisting of unsaturated fatty acid esters, characterized in that an agent is applied to the surface of the shaped body that reduces the stickiness of the surface. 2. Shaped body according to claim 1, characterized in that that the agent consists of a soap of the following general formula 'O ■ R - C - Ο ^θ M® where R is an alkyl radical having 8 to 22 carbon atoms and M is an alkali metal ion or an ammonium ion. 3 · Shaped body according to claims 1 or 2, characterized in that the surface treatment agent with a the foam preventing additive is mixed. 4. A process for the production of moldings, in particular in the form of granules, with reduced stickiness from a copolymer of ethylene and unsaturated fatty acid ester, according to claims 1 to J >> characterized in that the moldings are immersed in a dispersion which contains the Contains anti-tack agents. 5, The method according to claim 4, wherein the copolymer 609814/1193 is extruded through a nozzle into a water bath and cut under water by means of a knife, characterized in that that the surface tackiness reducing agent is added to the water bath in which the knife operates. 0 9 8 14/1193