DE8502398U1 - Foamed plastic particle for the production of packaging material - Google Patents

Description

HOECHST AKTIENGESELLSCHAFT HOE 85 / F D17 + H Dr.ZR / mü Foamed plastic parts for the production of packaging material

Packing or filling materials made from loose foamed plastic particles are known and are used in large quantities. The decisive factors for this are, above all, their freedom from dust, their resistance to moisture and mold formation, their abrasion resistance and their inert behavior towards the packaged goods, as well as their ββι · 1ηβββ ßotrl r »V» +. . tt >> l λ nYiofviai aa ueriian aninho Vn η α-fca-fco-PP-

particles as compact, non-foamed containing blowing agent Granules made available and only in the packaging plant according to known processes for the final Foamed shape.

The effect of the foamed plastic particles as a packing material is based on the fact that after embedding the Packaged goods interlock or interlock and also enclose a large volume of cavities. The void volume is the volume enclosed but not filled by the particles when pouring to the pile. As a result, a kind of "resilient shell" is formed around the material. The mutual Toothing with the simultaneous formation of a large cavity volume is particularly important to prevent the "wandering" of the to prevent the packaged object through the packaging particles as a result of the transport vibration and to achieve an optimal permanent "spring effect".

In contrast to the ability to interlock with other particles and thereby create a large void volume form, the requirement is that the particles forming the packing material also have good flow properties exhibit. The light, foamed plastic particles are usually from storage silos

placed in the free pallet in the respective packing containers. A prerequisite for this is that the particles are able to flow properly, otherwise they will become entangled of the particles a "bridge formation" takes place in the storage bunker and the even outflow and thus the dosage of the particles is disturbed or prevented. Especially with fully automatic packaging systems this leads to sensitive disturbances.

Attempts have been made to shape the foamed plastic particles in a certain way, these contradicting one another To meet the requirements of the packaging material, i.e. with a large cavity volume and good interlocking or interlocking the particles in the packaging container also have good flowability when they are removed from the storage container to reach. Examples of the shape of the particles are: S-shape, Y-shape, star shape, corrugated elongated or round leaves, rings, slit rings, 8-shaped hollow bodies, spiral bodies, Particles in the shape of potato chips, hemispheres, saddle-shaped particles, and dumbbell-shaped particles Flakes.

The above-mentioned particle shapes often show satisfactory interlocking properties with acceptable flow properties, but the void volume, which is essential for the packing behavior, remains below the desired size.

The object of the invention was therefore to avoid the disadvantages of the known particle shapes and, in particular, a to provide foamed plastic particles for the production of packaging material that has good flowability, a good gearing properties and at the same time a great one Has void volume in the pouring to the pile.

To solve this problem, the invention proposes a foamed one Plastic particles in star shape, which is characterized in that the plastic particles are from a star-shaped or cloverleaf-shaped base body with at least derives three legs lying in one plane and has at least one omission.

According to the invention, the number of legs is at least three, especially three, four, five or six. Preferred are, according to the invention, particles that have three or six limbs.

The omission (s) of the packaging material particle according to the invention can (can) be in one of the legs or in the Center of the particle. According to the invention, a particle is preferred which has omissions in all legs having; Furthermore, such a particle is preferred in which the omission is only in the center, what applies in particular to a six-limbed particle. If the omissions are only relatively small and their Moved size in the lower part of the ranges mentioned below, it can in some cases be favorable next to add an opening in the center of the packaging material part center to the openings in the thighs.

The openings are preferably predominantly round to oval or lenticular in shape; however are fundamental other shapes, such as polygons, for example triangles, squares, hexagons, etc. are also possible.

The size of these openings is generally dimensioned so that their area is about 25 ^ to about 75 ^, preferably 30 4 to 60 #, based on the respective leg area or on the total area with only one opening in the center. The diameter or the largest clear width of this recess (s) is mostly 3 to 15 mm, preferably 6 to 12 mm. Basically

ft - "'

is the size of the omissions in the packing material particles, as in the granular particles, is not critical and can be greater or lesser than those given above Take percentages, but then with the risk of certain disadvantages.

Me. The wall thickness of the packing material particle according to the invention is generally from 8 to 20 mm, preferably from 10 to 16 mm, the wall thickness being generally greatest in the center of the particle and decreasing towards the edge regions. Under certain circumstances, this drop can be up to 70 ^, in particular up to 50 K> .

The dimensions (A '), (B ¹ ) and (C) in the case of a three-legged particle (cf. FIGS. 3 to 5) are mostly 16 to 40 mm, 16 to 40 mm and 8 to 20 mm. The corresponding preferred values are 20 to 38 mm (A '), 18 to 36 mm (B') and 10 to 18 mm (C). The angle α 'between the legs 2 and 4 (Fig. 3) expediently moves between 100 and 140 °, preferably 100 and 130 °.

In general, in the case of three-legged particles, the ratio of (A ') to (B') is 1: 0.4 to 1: 2.5, preferably 1: 0.5 to 1: 1.8, the ratio of (A ¹ ) to (C) 1: 0.2 to 1: 1.25, preferably 1: 0.26 to 1: 0.9 and the ratio (B ') to (C) 1: 0.2 to 1: 1.25 , preferably 1: 0.25 to 1: 1.

The dimensions, angles and proportions of a four-, five-, six- and multi-limbed particle are entirely corresponding

30th

The surface of the packaging material particle according to the invention contains one more or less depending on the degree of foaming, etc. large number of cracks (craters) caused by the escaping propellant.

35

The void volume of the unshakable bulk of the packaging material in question (determined according to the below

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• t ► ·> ·· · ft ·

··· · · ti in

"described measuring method) is generally more than 60 #, preferably 65" to 90 ¥>, in particular 65 to 80 ^.

Due to the star-shaped, omitted shape of the packaging material particle according to the invention is not only a particularly large cavity volume Formed bed, but in addition there is an elastic deformation behavior of the particle without permanent deformation or even destruction of the foam structure occurs.

The plastics commonly used for this purpose are suitable as plastics for the packaging material particles according to the invention Thermoplastics such as styrene polymers, polyolefins such as polyethylene, VC polymers and the like. Preferred polystyrene is used.

The inventive packaging material can also contain the usual additives such as flame retardants, UV and Heat stabilizers, dyes and externally applied Containing finishing agents in the usual quantities. i

The production of the packaging material part according to the invention | chens happens in such a way that first a corresponding |

A corresponding foamable, blowing agent-containing granulate particle is produced, which is then foamed to form the packing material particle. The compact plastic granulate is produced in a known manner by melting the plastic in an extruder, metering a suitable blowing agent under pressure into the plastic melt, pressing the blowing agent-containing melt through a corresponding star-shaped (clover-leaf-like) mold opening and then granulating »This mold opening is with mold cores (thorns ) provided whose ^; The shape and number correspond to those of the desired omissions. To prevent foaming during extrusion

dem, are the strands emerging from the extruder cooled quickly, expediently by means of a water bath. The length of the most favorable water bath section and the withdrawal speed of the strands can be determined by a person skilled in the art easily determined by a few routine tests. Then the cooled strands are perpendicular to the Peel direction cut into particles of the thickness given above. The strand temperature should expediently be chosen so that the proportion of dust and Splintering when cutting is as low as possible.

The resulting expandable particle can then be heated above its softening point, e.g. by water vapor, are foamed to form the packing material particles according to the invention; this foaming is usually carried out only carried out by the consumer. Instead of a physical blowing agent, the plastic can also be used before Extrusion a chemical blowing agent that releases gases, e.g. water vapor, carbonic acid or nitrogen when heated, be mixed in.

The produced therefrom packing material consists predominantly, preferably more than 90 Ά and inabesondere more than 95 i> of these particles with the above described shape, the shape of a star or clover leaf ie with three, four, five or more, preferably three or six legs lying in one plane, each leg having at least one opening (a hole). Without departing from the scope of the invention, however, at least a part of it can also have a slight curvature, for example such that all legs deviate from an imaginary plane in the same direction. In addition, individual legs in some particles can also be curved in opposite directions to one another. The angle of curvature (deviation from the plane) is a maximum of 20 ", preferably a maximum of 10 °.

The granulate particles obtained as an intermediate product in the process described above is built up analogously to the packing material particles formed therefrom by foaming. For example, the size of the openings in this 6-granulate particle is generally dimensioned so that their area is about 25 4 to about 75 4>, preferably 30 % to 60 i> , based on the respective leg area or on the total area at only an omission in the center. The diameter or the greatest clear width of these openings is mostly 0.2 to 2.0 mm, preferably 0.3 to 1.5 mm.

The wall thickness (cutting length) of this granulate egg is generally in the range 2.5 to 7.0 mm, preferably 3.0 to 6.0 mm.

The dimensions (A), (B) and (C) in the case of a three-legged granulate particle (cf. FIGS. 1 and 2) are mostly 4 to 6.5 mm, 4 to 6 mm and 2.5 to 7 mm. The corresponding Preferred values are 4.5 to 6 mm (A), 4.5 to 5.5 mm (B) and 3 to 6 mm (C). The angle ο between the legs 1 and 2 (Fig. 1) expediently moves between 100 and 140 °, preferably 110 and 130 ".

In general, it contributes to a three-legged granule particle the ratio of (A) to (B) 1: 0.6 to 1: 1.5, preferably 1: 0.75 to 1: 1.25 the ratio of (A) to (C) 1: 0.4 to 1: 1.75, preferably 1: 0.5 to 1: 1.4 and the ratio (B) to (C) 1: 0.4 to 1: 1.75 preferably 1: 0.6 to 1: 1.35

The dimensions, angles and proportions for a four-, five-, Six-limbed and multi-limbed particles are quite accordingly.

As stated, the legs of the granulate also lie predominantly in one plane. Slight deviations of the flat shape are also possible here.

m » ·· · ι · κ cm

The invention is explained in more detail with reference to the drawings. Figures 1 and 2 show a foamable three-legged granulate particle in a high magnification while FIGS. 3 to 5 relate to the packaging material particles according to the invention obtained therefrom by screwing fen. Figures 5 to 9 show others according to the invention

\ Embodiments of foamed particles again.

^ ₁ In Figure 1, which is a front view of a granulate particle

I 10 (1) shows, (2), (3) and (4) mean the three legs of the

I particle and (5) the omissions. Give (A), (B) and (C)

* the dimensions of the particle in the three spatial directions again. Ι α represents the angle between the two legs (2) and

1 (4).

i 15

I Figure 2 shows the particle (1) of Figure 1 in a side view. (C) means the wall thickness (cutting length).

FIG. 3 shows a packing material particle 20 (1 ¹ ) according to the invention, which by foaming the granulate particle (1)

of Figure 1 was created. (2 ¹ ), (3 ¹ ) and (4 ¹ ) mean I turn the three legs, (5 ¹ ) the omissions, while

K (A ¹ ), (B ¹ ) and (C) are the dimensions of this particle in the three

¹ S express spatial directions, α 'is the angle between

* 25 the two legs (1 ¹ ) and (3 ¹ ) again.

j FIG. 4 shows the particle (1 ·) of FIG. 3 in section

J. IV - IV. (C) therein means the thickness.

• ·

Examples

Dag packing behavior of foamed plastic particles is essentially determined by the bulk density, the void volume and the pourability. One in addition The cylinder drop test provides important information.

In the following table 1 these are the packing behavior * determining values of the packaging material made of the invention ;;

Tsilchsn äsnsn des packing material sesäS of DE = open I

Ψ Legunsschrift 2,848,338 compared. 1

The tests were carried out as follows and κ

are summarized in Table 1:. T

1 · Determination of the increase in bulk density of the bed by shaking

A measuring beaker with a volume of 10 liters and the dimensions D = 189 mm φ and H = 357 mm was filled with packaging material particles in free fall with the aid of a test funnel. The test funnel was made of sheet metal with a smooth surface, had a slide in the • outlet and had the following dimensions:

large diameter 850 mm ± 5 mm

small diameter 150 mm ± 5 mm

Inclination angle 45 * ± 1 *

Overall height with outlet 700 mm ± 5 mm

Height of outlet 305 mm, distance slide - outlet end 25 mm ± 2 mm

Thickness slider 1.6 mm

Such a test funnel is described, for example, in "Technical delivery conditions TL 8135-0032, Issue 2 (March 1982) ", pp. 1 to 6 of the Federal Office for Defense Technology and Procurement of BR-Deiitschland.

Then the upper edge of the measuring cup was smeared with a ruler. The net weight divided by 10 gave the bulk density of the unshaken bed in grams per liter.
5

2. Determination of the bulk density of the vibrated bedding: the measuring beaker described under 1) was filled with packaging material particles in free fall with the aid of the test funnel also described under 1). During the filling process, the measuring cup was pushed open on a solid base at short intervals until there was no further volume contraction of the bed. The measuring cup was then smeared with a ruler. The net weight divided by 10 gave the bulk density of the vibrated bed in grams per liter.

3. Determination of the compaction of the bed by vibration (vibration compaction):

The compression of the bed by shaking resulted from the quotient

(Bulk density of vibrated bed - bulk density of non-vibrated bed). 100 / bulk density unshaken Bulk

in the present cases to:

[6.4 (6.0) g / L - 5.4 g / 11. 100 _{= uu 4} 5.4 g / l

4. Determination of the void volume of the unshaken bed.

The above measuring beaker was filled with packaging material as described under 1). After painting over the top of the measuring cup with a ruler

the measuring cup closed with a wire sieve. Then the measuring cup would be immersed in water and on all sides turned so that all voids of the bed filled with water. That for pulling the The volume of water required for cavities corresponded to the volume of the cavities in the non-vibrated bed.

5 · Determination of the void volume of the vibrated bed .

The measuring beaker in question was filled, as listed under 2), and shaken until the particles were packed as tightly as possible Then the measuring beaker was immersed in water and turned on all sides so that all cavities are with it Filled with water. The volume of water required to fill the cavities corresponded to the volume of the cavity vibrated bulk.

6. Determination of the flow time (flow behavior);

This experiment was carried out five times. The foam particles were air-conditioned up to (Jewicht constancy to standard climate 23 / 50-2 DIN 50 OH . The outlet of the funnel described under 1) was closed with a slider and the one to be tested Material filled to the brim. Then the slide was pulled out and the time to complete Leakage measured.

7. Determination of the penetration depth in the cylinder drop test: The test set-up used for this is described

in the company brochure of HOECHST AG "^ 'Hostastar" (September 1981 edition).

A steel cylinder weighing 1.65 kg (diameter 44 mm, Length 140 mm) from a height of 1 m into a container filled with packaging material and shaken briefly. ter (diameter above: 420 mm; diameter below: 360 mm; filling height: 370 mm) dropped.

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The cylinder impinging with the horizontal longitudinal axis only caused a short-term deformation of the

I Bulk of packaging particles And then jumped off the level

:. the filling level is dampened. Only "the second ^up; '5 hit the bed penetrated the steel cylinder ^ slightly into the bed one, but remained in this

i Position fixed (Table 1, packaging material i). From the-

) | stood from the level of the fill level to the penetrated

'■; ·; lower metal line of the steel cylinder is used as a

'>' -. 10 penetration depth specified in cm.

I ⁸ · Springing back of the cylinder from the surface of the

I bulk.

With this assessment criterion, the

15 Packing and fixing properties of packaging bulk

differentiate well. If there is no spring back when the steel cylinder hits the bed for the first time, so the penetration depth is always greater than with bulk packaging, which due to their good interlocking

20 and upholstery properties force the steel cylinder to spring back and only very low penetration depths when allow the second or third impact on the bed resulting from the springback.

Table 1: Bulk density
unshaken bulk dimension g / l I. Yes A. Yes Bulk density of
vibrated bulk s / i 5.4 7.2 1
5 Bulk density increase the
Raised by shaking 6.0 8.0 2 Void volume of the
unshakable bulk 11.11 11.1 3 Void volume of the
vibrated bulk 69 49 10 4 Trickling time lake 66 44.8 5 Penetration depth
Cylinder drop test cm 11.5 12th 6th Spring back of the cylinder
from the surface, the
Bulk /no 2 4th 15 7 irs
Yes 8th

I s packing material made of plastic particles according to the invention with oval to lens-shaped openings in all three legs; clear width of these openings approx. 30 4 to 60 K) of the respective leg surface).

A = packing material according to DE-Offenlegungsschrift 2.848.338.

From Table 1 it can be seen that the packaging material made of packaging particles I according to the invention in bulk density, Void volume, cylinder drop test, penetration depth and flow time is superior to the packing material from the particles A.

Claims (8)

-H- HOE 85 / P 017 + H SCHÜTZ ANSPRtTCHE -. . Foamed plastic particle in star shape, thereby characterized in that the plastic particle is from a star-shaped or cloverleaf-shaped body with derives from at least three legs lying in one plane and has at least one omission. 2. Foamed plastic particle according to claim 1, characterized characterized in that at least one of the legs or the center of the particle has an omission. 10 3 · Foamed plastic particle according to claim 1 and / or 2, characterized in that the opening is round to oval and / or lens-shaped. 4. Foamed plastic particle according to one or more of claims 1 to 3, characterized in that the area of the recess 25 is 4 to 75 ^ of the respective leg surface. 5 · Foamed plastic particle according to one or more of Claims 1 to 4, characterized in that the particle has three or six limbs, in particular three limbs is. 6. Foamed plastic particle according to one or more of claims 1 to 5, characterized in that the thickness of the particle is 8 to 20 mm. 7. Foamed plastic particle according to one or more of claims 1 to 6, characterized in that the particle is three-legged and the dimension (A ¹ ) 16 to 40 mm, the dimension (B ') 16 to 40 mm and the dimension (C) 18 to 20 mm. - 15 - HOE 85 / F 017 + H 8. Foamed plastic particle according to one or more of claims 1 Ms 7, characterized in that the void volume of the non-vibrated bed is at least 60 4> "in the bed to the pile. 9 · Foamed plastic particle according to one or more of claims 1 to 8, characterized in that the particle consists of polystyrene and with one per se usual blowing agent was foamed.