DE2150282A1 - Process for the production of polypropylene plastics - Google Patents

Description

II * · ·

EIKEN3ERG & BRÜMMERSTEDT

PATENT LAWYERS IN HANOVER

Kimberly-Clark Corporation, 240/518

Process for the production of polypropylene plastics

The invention "relates to a process for the production of Polypropylene plastics with improved elasticity.

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For some time it has been known that polypropylene polymers, especially polypropylene in the crystalline (isotactic) state very particularly good'-for production ' of foils and other extruded products are suitable. Thin films made of polypropylene are used for Sotmmpi-Verpaokung, they can also be coated or laminated to form a heat sealable wrapper material. Furthermore, pipes for pipelines or threads for synthetic fibers, leppiohe, ' Extrude ropes etc. as well as molded parts for washing machines, televisions, suitcases, packing boxes and similar articles to shape. In general it can be said that there is always someone who is steep or hard materials are required, the average The degree of crystallinity of the material must be high. Ii Crystalline 2uitand, polypropylene has a gaaa au »jjeleiehaete Resistance to solution attacks, Fats and oils and also against acids, JLlkaliea around * some other aggressive chemicals.

Polypropylene polymers are also extremely favorable in terms of many other properties. Particularly noteworthy are a high yield point and rigidity, a high deformation temperature, good surface hardness and good resistance to stress fractures. The dielectric properties are also excellent, and "the impact resistance at normal temperatures is good (although the material tends to become brittle ^{below about 25 ° C.).}

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BATH ORIGINAL

For certain use cases, however, such as for blown film processes and Kaitreck processes the properties of commercial polypropylene polymers have not yet proven to be sufficiently satisfactory. the This is because hitherto known polypropylene polymers do not have particularly good extensibility. The ability of the material However, to stretch quickly without tearing and breaking. a very important material property for the processes mentioned because if the elasticity is insufficient, the time required to stretch and stretch the material becomes becomes too big.

With the invention, the known polypropylene plastics to the extent that they can also be easily and well stretched at high speed, so that reduced costs in the Blaefilm process and Kaltreok process can be. The invention accordingly provides a process for the production of polypropylene plastics with improved elasticity, which sioh thereby indicates that with a fully polymerized polypropylene a small amount of maleic anhydride and an aromatic one Compound with a tertiary benzylic hydrogen atom be mixed and fused.

By the method according to the invention, the melting and solution viscosity of the polypropylene polymers increased.

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COPY

For example, films with the inventive Mixture extruded, higher melt viscosities than are normally inherent in polypropylene polymers, so these films feel good cold at high speeds let stretch. As a result, the films obtained in this way are stronger than those made under comparable conditions with a known, unmodified polypropylene polymer were manufactured.

The proportions of malei: * acid * anhydride and the said aromatic compound in the mixture are not critical. Additions of about 0.05 to 5 parts by weight of maleic anhydride and from about 0.2 to 10 parts by weight of said aromatic compound, each per 100 parts by weight of polypropylene polymers, are found to be suitable proven. Preferred ranges are from about 0.05 to 2 parts by weight of maleic anhydride and 1 to 5 parts by weight of the aromatic compound.

v The term "maleic anhydride" used above and also in the claims means the compound preferably used, but is also expressly intended to include other compounds with similar properties, such as, for example, organic radical formers in equivalent amounts.

The following are exemplary embodiments of the invention

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explained, it being mentioned that all mentioned in the examples Unless expressly stated otherwise, quantitative data are parts by weight.

example 1

This example serves to explain the method according to the invention and the results that can be achieved in principle. Several samples of different compositions were produced from polypropylene (PP) or from mixtures of polypropylene with polystyrene (? 3) and / or maleic acid anhydride (MA), for which the inherent viscosity and the melt index were determined for the purpose of comparing the properties . The "inherent viscosity" is the specific viscosity divided by the concentration, and it was measured at a concentration of 0.5% in p-xylene at 100 ⁰ C with Einei | Sargent viscometer Fr. 50. The determination of the melt index was carried out on two samples at 190 ⁰ O and 230 ⁰ C and with a further sample only at 230 ⁰ C, in each case according to the method ASTM No. D-1238- 65T using a 62 pg weight with a Tinius Olson melt indexer.

Isotactic polypropylene, commercial atactic polystyrene and maleic anhydride in powder form in a weight ratio of

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40: 2: 1 intimately mixed with one another. The polystyrene was the material "Dow's Styron No. 685" »which has a melt flow of 2.4 g / TO min according to ASTM D-1238-62T. A film was formed from this powder mixture by pressing two grams of this mixture for 2 minutes at 200 ^° C. and a pressure of about 2100 kg / cm.

In the same way, a sample 1b was prepared in the form of a Pilms are made, but using polypropylene, polystyrene and maleic anhydride were mixed together in a ratio of 100: 2: 1.

For comparison purposes, samples Ίο to 1f were again produced in the same way and formed into films. Sample 1c consisted of pure polypropylene, sample 1d was made from a mixture of polypropylene and maleic anhydride in a ratio of 100; 1, and samples 1e and 1f were obtained from a mixture of polypropylene ψ and polystyrene in a weight ratio of 40: 2 and 100: 2, respectively.

The inherent viscosity of all samples was determined in the manner already mentioned with a Sargent viscometer No. 50. Furthermore, the melt index for samples 1b and 1c was determined in the manner also mentioned with a Tinius Olson melt indexer, namely at 190 ⁰ O and 230 ⁰ C. Similarly, was also the sample of Schselzindex at 230 ⁰ C 1e yet determined. The results of the Linxeruchungen are

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in the following table 1 _t laid down

relationship
PP / PS / MA TABLE 1 1 90 Melting index
g / 10 min
⁰ C 230 ⁰ C 1 sample
Fr. 40: 2: 1 inherent
viscosity 9 1a 100: 2: 1 2.70 1 ,1 4, 1b 100: -: - 2.92 1 ,8th 13, 6th 1c 100: -: 1 1.56 1d 40: 2: - 0.72 6, 1e 100: 2: - 1.9 1f 2.0

From the values in Table 1 it can be seen that By adding a small amount of polystyrene to the polypropylene, the melt and solution viscosity of the Polypropylene can increase slightly, while an addition of potassium anhydride to the polypropylene a drastic one shows the opposite effect. It is therefore surprising that the combined addition of a small amount of both on polystyrene as well as on maleic anhydride to polypropylene quite a substantial increase in melt and solution viscosity the mixture can be achieved.

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-B-

Example 2

In this 3eispiei i & t shown that the component Polystyrene of the mixture through, another compound with one tertiary benzylic hydrogen atom can be replaced. This was the effectiveness of cumene (GU), m-di-isopropylbenzene (DIPB) and 1,1-diphenylethane (DPE) were investigated.

In the manner already explained in Example 1, films were produced from samples of the general composition 40 ropes of polypropylene, 2 parts of cumene or m-di-isopropylbenzene or 1.1 diphenylethane and 1 part maleic anhydride. the Results of the measurements of the inherent viscosity on these, Samples labeled 2a to 2c are in the following Table 2 summarized.

. '"DT ¹ T

ι-. rSP. I I.

Pro b e ratio 3

2a PP / Cü / KA: 40/2/1

2b? Ρ / 3ΙΡ3 / λΑ : 40/2/1

2c PP / DPE / Ιΰ. : 40/2/1

mhär duck Vislco s ιτό.τ 1, 56 2, 43 2> S9 2, 5

BAD OBiQlNAL

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The values in Table 2 can be used in conjunction with the values according to Table 1 deduce that the magnification the inherent viscosity in the method according to the invention occurs, sieve, generally for the combined use of maleic anhydride and a compound of the general Formally

H
I.

A. - C - R

can lead back. Ih of this general formula mean: an aromatic residue ■

1 is an aliphatic radical

either an aromatic or an aliphatic radical

Ss can thus be seen that the through this general formula characterized compound around, oina compound acts with a tertiary benzylic hydrogen atom.

From Table 2 it is apparent, furthermore, that the aromatic compound with tertiary asu bsnzylischen hydrogen atom need not necessarily be zn --- polymer to in combination

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nation with the maleic anhydride the considerable viscosity s increase.

Example_3

Generally it was used in improving the properties of polymers by adding additives such as a.B. Plasticizers, have often been observed to improve a particular Property at the expense of the other properties, i.e. accompanied by a deterioration in other properties will. In the present case, on the other hand, it can be said that at the polypropylene mixture produced according to the invention no adverse effects with regard to the other material properties occur.

A sexton measuring 6.35 x 63.5 mm was made from the film of Sample 1c and stretched in an Instron tensile machine at a rate of 2 cm / min. The sample showed Ice ine P "necking" and broke at a stretch of $ 5.8. At a lower rate of 0.5 cm / min, "constriction" occurred at room temperature. On the other hand, a corresponding sample of uczi film material according to samples 1a and 1b could at a rate of 20 cm / min up to an elongation at break of 700 $ be stretched. On the other hand, the strength properties of the sample obtained from sample 1a in the cold-stretched state were fully comparable with those of the sample obtained from sample 1c;

IAD ORIGINAL

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appropriate differences, shown in Table 3.

TABLE 3

Sample breaking strength initial module kg / cm kg / cm ²

1a 112 6.563

lc "134 6.637

From the above it follows that3 the polypropylene-Ilschungen produced according to the invention especially good for performing faster and therefore more cost-effectively Stretching Yorgangs are suitable. ! Leave with that they look better than the delicious polypropylene polymers use in blown film or cold stretching processes and process them into products, e.g. for the production of packaging films, Films for electrical capacitors and synthetic papers can be used.

BATH ORIGINAL

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The neohanism of the method according to the invention is not yet known. The improvement is likely to result dör physical properties, especially the Extensibility, from an increase in molecular weight as a result of a graft mechanism.

In all the preceding examples was w of polypropylene assumed as Deia to enhancing polymers, since polypropylene is currently the w ^ icht.igste polymers with a tertiary (aliphatic) hydrogen atom. However, the invention can also be used equally well with all other polymers with a tertiary hydrogen atom, i.e. with polymers of the general structure

(-CH ₂ - CH-R

where R is an alkyl radical. The w term "polypropylene" used in the claims is therefore generally to be understood that also ar-dare polymers of the same general structure with a .schlossen ".

_T>

Patent claims

KHS / kä

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Claims (5)

- patent claims - 1 . Process for the production of polypropylene plastics with improved extensibility, characterized in that a small amount of maleic anhydride and an aromatic compound with a tertiary benzylic hydrogen atom are mixed and fused with a fully polymerized polypropylene. 2. The method according to claim 1, characterized in that aas maleic anhydride in an amount of about 0.05 to 5 parts by weight and the aromatic compound having a tertiary benzylic hydrogen atom in an amount of about 0.2 up to 10 parts by weight are used, each based on .100 parts by weight of polypropylene polymers. 3. The method according to claim 1 or 2, characterized in that the aromatic compound with a tertiary benzylic hydrogen off-AtGii is a compound of the general formula H
A _r -C- R ₁ Marg 20981 6/1592 is used in the Α., An aromatic residue R _{1 is} an aliphatic radical "and Rp is an aromatic or aliphatic one Rest is. 4. The method according to any one of the preceding claims, characterized in that isotactic polypropylene is used as fully polymerized polypropylene. 5. The method according to any one of the preceding claims, characterized in that polystyrene, cumene, m-di-isopropyrbene sol or 1,1 diphenylethane are used as the aromatic compound ηit a tertiary benzylic hydrogen atom. 209816/1592