DE3150154A1 - Process for the preparation of flowable pastes from a plurality of polyvinyl chloride polymers which cannot be made into pastes individually - Google Patents

Abstract

Process for the preparation of flowable pastes from a plurality of polyvinyl chloride polymers which cannot be made into pastes individually, by gelling PVC polymer under mechanical flexing with addition of a plasticiser or plasticiser mixture. First, a mixture of various polymers having a spherical, compact particle structure is prepared in a classification which gives a spherical packing which fills at least 50% of the space, and the mixture is subsequently initially gelled by means of the plasticiser or plasticiser mixture in such a manner that only microgelling of the glassy surface takes place.

Description

The invention relates to a method for producing flowable pastes made of several polyvinyl chloride polymers that cannot be pasted individually by mixing with plasticizers.

The main problem in making flowable PVC pastes and their use in further processing consists in achieving a sufficient service life of the obtained dispersion, i.e. the prevention of settling or segregation in the time between production and further processing. As the common PVC types meet these requirements even when using dispersants and adhering to them special procedural conditions are not sufficient for the

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Special PVC types have been developed for the purpose of paste production have been, which give sufficient flowable pasty masses, but regardless of their costly production method no satisfactory result due to various polymerization processes Show service life behavior but have to be processed shortly after paste production.

It is also known that in the above described Way manufactured PVC pastes so-called viscosity regulators

LO · to be added, including, among other things, as a viscosity-reducing agent non-paste-forming PVC types, ■ generally PVC suspension polymers, can be added. Other viscosity reducers ■ are about secondary plasticizers, thinners such as testben ^ in and alkylbenzenes as well as surfactant substances that already

L5 with an addition of between 0.5 and 2 % cause a noticeable reduction in viscosity. In a corresponding manner, colloidal silica, metal soaps, aluminum and magnesium silicates and copolymers of vinyl chloride are used to increase viscosity. However, all these additives have in common

[Q that they contribute little or nothing to paste formation, ie to the dispersion of the PVC grain in the plasticizer, that is to say that although they influence the physical properties of the pastes, they do not improve the service life. The production of PVC pastes with long-term stability

! 5 did, i.e. such pastes that last for at least six months

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without separation of sediment or even segregation at changing temperatures between -10 ° and + 40 ° without Effects on the behavior during further processing can not be stored up to now. 5

The object of the present invention is to create a method with the aid of which pastes with long-term stability can be produced using any types of PVC, that is to say also the types of PVC previously regarded as non-pastable. The invention consists in first producing a compact spherical polymerizate of a specific space filling of at least 50 % resulting in a granular classification, and the polymer thus obtained is subjected to a microgelling process with the addition of plasticizer to produce a superficial gelation of only the glassy grain surface.

The invention i ^ st created a method with which

as
Help also hitherto / not pastable · respected PVC types can be processed into pastes with long-term stability without any problems, so that for the first time it is possible to obtain inexpensive pastes as well as their transport and long-term storage at fairly wide temperature limits with a corresponding expansion of their possible uses. Here, the microgelling of the glassy grain surface falls to the task,

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the friction between the PVC particles and the liquid plasticizer phase to increase in such a way that the frictional force at least compensates for the downward falling force component, so that the particles in this way in the liquid plasticizer phase held in abeyance and grounded.

Excellent results are already achieved with a polymer which is approximately 50% filled in space. In this sense, the use of homogeneous Kugelpoly _me risat, ie of spherical polymer, with the same diameter of the spherical elements, with which - regardless of the diameter of the spheres in detail - ^ Rium filling of 52.4 % is achieved. Much better results are achieved with heterogeneous spherical polymers in the sense that spherical polymers are used in two or more classifications that are specifically tailored to one another with regard to grain size and quantitative ratio.

In this sense, the pastes are advantageously produced using polymers of two or more different types of PVC that cannot be pasted, and the resulting PVC mixtures expediently form mixtures of two grain size classifications that are matched to one another in such a way that the spheres of the smaller size classification have a diameter of 20 to 25 % , preferably 22. % of the diameter of the balls of the larger classification and a proportion of the

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Total mass of 0.5 to 0.7 % by weight, preferably 0.6% by weight. When using such a granulate mixture, the offset, interlocking deposits of the balls with the larger diameter result in a space filling of 60.445 % by the granulate of the larger classification and of 0.415 % by the granulate of the smaller classification, so that overall with such a size and By weight proportion of the grain spectrum of the granulate, an optimal space filling of approx. 61.0 % is achieved.

However, very good results are also achieved when using PVC granulate from mixtures of three size classes, of which the balls of the middle class have a diameter of 35 to 45 %, preferably 41.5 % and a proportion of 5 to 8% by weight , preferably 6.8 wt .-? o and the balls of the small classification a diameter of 6 to 10%, preferably 8.5% of the diameter of the balls of the major classification and a proportion of 0.3 to 0.5, advantageously 0 , 4% by weight of the total mass. In this way, too, an excellent filling of the room of around 56 % is achieved. Correspondingly good degrees of filling are achieved with a pile of balls in which the proportions belonging to the individual grain size classes are grouped in the specified ratios to one another. The production of PVC mixtures of these classifications is possible without difficulties, the resulting mixture

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mixed should not contain itiehi as 6 to 8 wt .-? o and preferably 3 to 5 ß "/ i-? o · fine grain <5 μ ·· πι as carrier grain, whereby the oil stability is further improved significantly.
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The ffers division of the festivities is advantageously carried out by einöder Repeatedly working through the mixed with the plasticizer PfyC mixture on a one- or three-roller mill if a working temperature of 35 ° C + 3 in IQ the paste, causing the gelling process on the top grain layer is limited.

The invention is illustrated below in an example.

The sieve analysis of samples of two considered non-pastable PVG grades (type I, II) resulted in what is shown below Grain spectrum:

Red. Grain size / i «( _G ew! -S) (Ge" - *)

150 80 30

25 ²⁰

85 , 2 3.5 11 , 6 23.2 3 , 2 60.7 - , - 6.6 6.0

The grains of the polymers showed a compact spherical shape and glassy surface.

It was a mixture of one part of the polymer Type I made with three parts Type II polymer. The mixing from a Drais laboratory mixer took place during a time of 5 minutes. The resulting mixture has the following composition:

Reduced grain size /.m ^ ^, sum

150 80

15 30

85.2 10.5 95.7 11.6 69.6 81.2 3.2 182.1 185.3 -, - 7.2 19.8 30.6 18.0

Of these, the grain group "150" is ideally filled with the grain group "30", of which 185.3 χ 0.6 / 100 (0.6 Geu /.- äS = 184.1 g remain, as well as the grain group "80" with the grain group "20", of which 19.8 - 0.2 = 19.6 g remain. The grain group (20 + 30), ie 184.1 + 19.6 = 203.7 g is filled with the grain group " 5 ", where 18.0 - 1.2 = 16.8 g

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lag behind. The grain group "5" continues to fill up alone or provides floating PVC grains. The grain of grain group "5" is used in certain proportions as' carrier grain. It is necessary that the storage-stable Paste the carrier grain at least 2 to 5 Geu /.-? I but not makes up more than 6 to 8% by weight.

The granules produced in this way are of the same weight a plasticizer mixture consisting, for example, of equal parts of DOP and Uni BB, and mixed again for 5 minutes, whereupon the mixture rubbed through on a 0 200 laboratory three-roll mill three times at approx will. The resulting paste shows no segregation and no precipitates. The specific theological properties were after one year of idle time as follows (measured in a torque meter (rheometer) "Rheomat-15" from Contraves-Industrieprodukte GmbH, Stuttgart):

- at J "170: 65.4 / 77.9 P (increase: 19.1 %) 20 - at J * 410: 47.1 / 60.6 P (increase: 22.3 5S)

- at J ^ 2580: 37.6 / 43.6 P (increase: 16.0 %).

Furthermore, two examples of optimal space backfills are given below, with the space backfilling in FIG. 1 of alternative 1 reproduces in which the grains

of the larger classification are deposited in the cavities of the underlying layer and the smaller balls 2, which have a diameter of 11% of the diameter of the larger classification, largely fill the remaining space.

In Fig. 2 there is another alternative with three spherical balls Classifications reproduced. The balls 3 of the largest classification are in the so-called closest packing of balls and the balls 4, 5 of the two graded smaller classifications gradually fill the remaining cavities in the specified Way. ·.

Tables 1 and 2 show the possible classifications or diameter ratios corresponding to the two alternatives 1 and 2 of balls 1 and 2 (Table 1) on the one hand and balls 3, 4 and 5 (Table 2) on the other. Table 3 gives the alternative maximums based on this Degree of filling again. The table shows that if the diameter and quantity ratio of the granules is adhered to, independent the same degree of filling can be achieved throughout the diameter of the base grain. In the table are in column dl / d'i is the proportion of the backfill achieved by the largest grain in alternative 1 (Fig. 1) and alternative 2 (Fig. 2). Columns d2 and d3 show the percentages of l / fulfillment

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through grain 5 bz \ i /. 6 (Fig. 2) in alternative 2 and column d'2 the proportion of grain 2 in the backfill in the case of the alternative 1 (Fig. 1)

Under the column "total space backfilling" they are from the five columns on the left to calculate the sums of the filling of the room listed after alternatives 1 and 2.

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T a_b_e_l_l_e ii'ill.Ko ^ SK ^ ßf'jiMjKtometer ^ A & JjiO 1 54

d'l d'2

500 110

250 55

150 33.0

120 26.4

100 "22.0

80 17.6

60 13.2

40 8.8

20 4.4

T_a_b_e_l_l_e 2_: grain size_ {micrometerJ _- AIt ^ 2

dl d2 d3

500, 207.1 42.9

___ 103 ^ 55 21 ^ 45

150 (= 0.150 now) 62.13 120 49.70 100 41.42 80 33.14 60 24.85 40 16.57 20th 8.28

12.87 10.30 8.58 6.86 5.15 3.43 1.72

Tabel

Ball size

dl / d 1

d2

d3

d'2 total space filled Alt l: (d'l + d'2) Alt 2: (dl + d2 + d3)

0.52375

0.524

0.524 / 0.60445 0.038 0.524 / 0.60445 0.038

0 _Λ 524 0 _Λ 524

0.0026 0.00415 0.0026 0.00415 0.6085
0.6085

0.5646 0.5646

0 ^, 51916

0.524 / 0.60 * 45 0.038 0.0026 0.00415

0.524 / 0.60445 0.038 0.0026 0.00415

0.524 / 0.60445 0.038 0.0026 0.00415

0.524 / 0.60445 0.038 0.0026 0.00415

0.524 / 0.60445 0.038 0.0026 0.00415

0.524 / 0.60445 0.038 0.0026 0.00415

0.524 / 0.60445 0.038 0.0026 0.00415

0.6085
0.6085
0.6085
0.6085
0.6085
0.6085
0.6085

0.5646 0.5646 0.5646 0.5646 0.5646 0.5646 0.5646

Comments / a) Values rounded up

b) Data listed with an index relate to alternative 1, without an index to alternative

Claims (7)

Claims 1 »Process for the production of flowable pastes made of several individually non-blown polyvinyl chloride polymers by gelling PVC polymer with mechanical flexing with the addition of a plasticizer or plasticizer mixture, characterized in that first a mixture of different polymers with a spherical compact grain structure in a spherical packing with a minimum of 50 % space filling is produced and the mixture then IQ by means of the plasticizer or plasticizer mixture in this way is gelled that only a micro-gelation of the glassy surface occurs. 2. The method according to claim 1, characterized in that for the preparation of the pastes mixtures of non-pasteable PVC types of two grain size classifications are used so that the balls of the smaller size classification have a diameter of 20 to 25 %, preferably 225% of the diameter of the balls the larger classification and a proportion of the total mass of 0.5 to 0.7 wt .-? o, 20 preferably have 0.6 wt .-? O. 3. The method according to claim 1, characterized in that for the preparation of the pastes mixtures of non-pasteable PVC grades of three grain size classifications are adjusted to one another in such a way that the balls of the middle class have a diameter of 35 to 45 %, preferably 41.5%, and the balls of the small class have a diameter of 6 to 10 %, preferably 8.5 % Have the diameter of the balls of the largest classification, the balls of the middle classification having a proportion of the total mass of 5 to 8 wt .-? U, preferably 6.8 Geu /.-? O and the balls of the small classification of 0.3 to 0 , 5% by weight, preferably 0.4% by weight. 4. The method according to claims 1 to 3, characterized in that for the production of pastes of non-pasteable PVC grades the heaps of PVC grains are used, in which the individual grain size classes belong Quantities of parts are grouped together in the specified proportions. 5. The method according to any one of claims 1 to 4, characterized in that the microgelling by one or more times Working through the mixture mixed with plasticizer on a roller frame at a working temperature of approx 35 ° C + 3 ° C in the paste. -. 6. The method according to any one of claims 1 to 5, characterized in that the production of the paste using COPV -A- Polymerization of at least two different types of PVC takes place. 7. The method according to any one of claims 1 to 6, characterized ι characterized in that the polymer mixture has a proportion of little as 6 to 8% by weight, preferably 3 to 5% by weight of the smallest grain contains less than 5 μm.