WO2013057748A1

WO2013057748A1 - Trimmer line comprising a biodegradable polymeric material and a relative biodegradable polymeric material

Info

Publication number: WO2013057748A1
Application number: PCT/IT2012/000317
Authority: WO
Inventors: Francesco BERTON
Original assignee: Colplast S.R.L.
Priority date: 2011-10-17
Filing date: 2012-10-17
Publication date: 2013-04-25
Also published as: ITTO20110927A1

Abstract

The invention concerns a polymeric material with high mechanical and thermal performance which is at the same time biodegradable and comprising; 50 to 79% of polyamide 6 with the addition of caprolactam in a percentage between 5 and 20%, below also called monomerised polyamide 20 to 49% of copolyamide 6/66 0.5 to 20% of biodegradability promoting additive 0 to 10% dye. Said polymeric material is advantageously used in a line 2 for trimmer 1.

Description

"TRIMMER LINE COMPRISING A BIODEGRADABLE POLYMERIC MATERIAL AND A RELATIVE BIODEGRADABLE POLYMERIC MATERIAL"

TECHNICAL FIELD

The present invention relates to a biodegradable polymeric material, in particular for use in products to be extruded, rolled or moulded which require high mechanical performance.

Advantageously the polymeric material of the present invention is used in a line for rotary head motorised devices such as bush, hedge or grass trimmers, devices which will be collectively referred to below as "trimmers" .

Advantageously said polymeric material can also be used in different applications such as: monofilaments and bristles for industrial and road sweeping brushes in general, straps/strips for producing handles for containers of various types; accessories and small parts for agriculture and gardening, produced by injection moulding .

PRIOR ART

It is known that due to increasingly stringent laws and increased environmental awareness, there is an increasing market demand for classic traditional materials to be replaced with bioplastics, i.e. plastics obtained from renewable sources and/or compostable and/or biodegradable plastics.

Use of the most widespread bioplastics is limited, however, by the fact that they have inadequate mechanical characteristics, in particular they are not as tough as the traditional plastics and they have lower resistance to abrasion and high temperatures.

There is therefore an ongoing search for numerous new applications of- bioplastics- wit —high performance, in particular with high mechanical performance and resistance to high temperature. In particular this need is felt in the sector of trimmer lines.

Trimmer lines are ^'generally equipped with a combustion engine or an electric motor which rotates at very high speeds ranging from 3000 to even 10000 r.p.m. and are provided with one or more lines for cutting grass, hedges and similar materials, below also referred to for the sake of simplicity and overall as vegetable material .

High speed lines are able to sever grass and plants. For this purpose they must have excellent mechanical characteristics so that they can cut without quickly wearing out. Furthermore they must be flexible so that they can be wound up and at the same time also withstand the high temperatures reached during operation.

Polymers are generally extruded in various diameters and sections, for example with polygonal, square, pentagonal, · hexagonal, triangular, circular or star-shaped section.

A serious problem of the trimmer lines used so far is that they are generally made of non-biodegradable materials . This means that when the line wears out and breaks, it is left in the grass, seriously polluting it and limiting compostability and biodegradability. Non-biodegradable lines are generally left in the environment, for example at the sides of roads, and with each cut the dispersion of polluting material increases.

It is estimated that 25, 000 tons of trimmer line are consumed every year worldwide; all this material is not only polluting in itself, but also pollutes the environment and any compostable vegetable material.

Legal limitation of the use of non-degradable materials for the —production of trimmer lines has also been proposed, but currently- there is no line on the market which is completely biodegradable and at the same time maintains the high mechanical performance of the lines currently used in this specific application.

The patent US200303396 proposes solving the above problem by using a line made entirely of a resin from a renewable source such as PLA and in particular starting from a resin obtained from natural starch as described in the patent US5869647.

This line does not work, however: despite the suggestions of the patent, the resin does not have the necessary mechanical characteristics to be advantageously used in practice in a trimmer. The polymer line from renewable sources described in the patent does not appear to be available on the market and if a PLA line, for example, is fitted in a trimmer, it is obvious that this material will deteriorate almost immediately before it can be effectively used.

The patent US6061914 proposes the use of a much more complex line with an outer polyamide sheath and a core made of biodegradable material .

According · to the patent, this line should solve the problem because after biodegradation of the core, the polyamide line will be attacked both from the outside and the inside by atmospheric agents and therefore it will degrade more quickly.

Said line in no way solves the above problem, however. In particular the polyamide is not in the least degraded by the atmospheric agents, in fact polyamide objects are considered practically eternal and deteriorate only aesthetically over time.

The degradation of a line of this type would take decades and therefore provides no ready solution to the above-mentioned problems .

Neither of the patented solutions therefore solve the above problem and the search continues for a trimmer line that can be considered biodegradable and which therefore reduces pollution due to dispersion of the line in the vegetable material cut and in the environment.

SUMMARY OF THE INVENTION

A first object of the present invention is therefore to provide a trimmer line which has the necessary mechanical characteristics and which can therefore function at the high trimmer operating temperatures without wearing out too quickly and is at the same time biodegradable.

A second object of the present invention is to provide a line which is over 40% biodegradable in 180 days and 100% biodegradable in less than three years .

A third object of the present invention is to provide a polymeric composition that has good mechanical characteristics, resistance to high temperatures and is at the same time biodegradable.

According to the present invention, said objects are achieved by a line as claimed in claim 1 and by a polymeric composition as claimed in claim 10.

BRIEF DESCRIPTION OF THE FIGURES

For a better understanding of the present invention, it is now described also with reference to the accompanying figures which illustrate :

- figure 1 is a schematic representation of a trimmer comprising a line made of a polymeric material according to the invention;

- figure 2 is the biodegradability curve measured up to 180 days for a line made of a polymeric material according to the present invention; and

- figure 3 is the biodegradability curve estimated up to complete biodegradability of the line of figure 2.

DISCLOSURE OF THE INVENTION Below, by "biodegradable material" we mean material of a type that can undergo a physical, chemical, thermal or biological decomposition via ^' which the majority of the resulting compost decomposes into carbon dioxide, biomass and water.

Below, by "additive" we mean a material of various type which is added to the polymeric material to vary its chemical-physical characteristics .

Below, by "biodegradation additive" we mean a material of various type which is added to the polymeric material to increase its biodegradation over time.

Below, by "polyamide" we mean a polymer containing macromolecules with recurring amide groups .

Below, by "monomerised polyamide" we mean a polyamide to which a certain quantity of monomer has been added at the extrusion stage .

According to the present invention the trimmer 1 of Figure 1 comprises a line 2 for trimmer comprising a biodegradable material or polymeric composition with high mechanical and thermal performance.

The polymeric composition of the invention comprises:

- 50 to 79% by weight of polyamide 6 out of the total weight percentage of the material . A plasticizer is added to the polyamide 6 during the extrusion stage, in a quantity in the range between 5 and 20%.

- 20 to 49% of copolyamide 6/66;

- 0.5 to 20% of biodegradability promoting additive; and

- 0 to 10% dye.

It is particularly advantageous to use caprolactam as the plasticizer in a percentage of between 5 and 20%. Since caprolactam is a volatile substance, it is difficult to add it in a non-variable precise quantity and therefore the percentage of plasticizer added is generally referred to as a range of values .

Alternatively it is - also possible to use different plasticizers such as butylbenzen sulphonamide .

Advantageously the polyamide 6 is present in a quantity of between 60 and 75% by weight.

Advantageously the co-polyamide 6/66 is present in a quantity of between 25 and 35% by weight.

Advantageously the additive for promoting biodegradability is added in a quantity of between 0.5 and 5%, for example 1%.

The dye is optional and can be added advantageously in a quantity of between 0 and 30%.

Advantageously all the polyamides 6 known and currently marketed such as Radipol S35P, AQL40 Aquafil and 1030B UBE can be used.

Advantageously all the co-polyamides 6/66 known and currently marketed such as 5034MTX1 UBE, 5034TX25 UBE, Radipol CS 38LX02066 and Radipol CS 40LX0266 can be used.

Advantageously as biodegradability promoting additives, all the known additives such as oxo-degradable additives can be used, but copolymers of ethylene vinyl acetate with added ingredients of organoleptic-organic cultured colloids, natural fibre, for example ECM Masterbatch pellets^®, have proved to be particularly effective .

Advantageously the dye is a masterbatch dye.

The trimmer line is advantageously formed in a single extrusion operation with desired section and diameter without this changing the general characteristics of the invention.

From an examination of the characteristics of the line produced according to the present invention, the advantages it offers are evident .

Advantageously the polymeric material described above offers high mechanical performance also at high temperatures and at the same time a good level of biodegradabilit .

Some examples of embodiment have been described in order to illustrate the invention but it is clear that a person skilled in the art can make modifications to the type of material, such as the addition of further components, without departing from the object of the present invention.

EXAMPLES 1-4

Lines were formed consisting polymeric materials, composition as shown in Table 1.

Table 1

Where :

A = additive promoting biodegradability ECM MasterBatch pellets, on EVA base;

B = masterbatch dye .

The examples from 1 to 3 are comparative examples, while example 4 is a polymeric material according to the present invention.

The trimmer lines having circular section and diameter of 3 mm underwent a mechanical test, i.e. a comparative empirical test with trimmer.

The result of the tests highlights that the comparative examples from 1 to 3 do not have sufficient mechanical characteristics to be advantageously used as trimmer lines, in fact they snap in fractions of a second, while the line made of the polymeric material as in example 4 has wear times similar to the lines currently on sale.

EXAMPLE 5

The polymeric material of example 4 in table 1 underwent biodegradation tests to verify its biodegradability over time.

A biodegradability test was performed according to the protocol "Determination of ultimate aerobic biodegradability under controlled composting conditions - UNI. EN 14855".

The data obtained are given in table 2 and in the graphs of Fig. 2 and 3.

Table 2

DAY mean biodegr. %

0 0.00

3 -0.13

5 1.41

7 2.62

10 4.16 12 4.84

17 6.38

21 9.00

27 13.16

33 18.67

41 24.78

48 28.14

56 33.38

66 36.87

75 38.08

83 39.49

92 40.49

102 41.30

112 41.70

124 43.79

133 43^'.65

151 45.20

162 45.80

180 46.67

220 49.01

280 52.66

420 60.69

620 72.34

900 88.67

1095 100.02

The complete biodegradability values were extrapolated from the values obtained up to 180 days, thus mathematically predicting complete biodegradability.

Therefore on the basis of the real data recorded over 180 days of activity in a composting process, extrapolated by mathematical/statistical model (TREND) , it can be affirmed that the line of example 4 reached 46.67% of biodegradability in 180 days and will reach 100% biodegradability in approximately 1095 days .

The data recorded allow certification of said item as complying with the European Directive EC 94/62 with reference to aerobic biodegradability. The same data also indicate an intrinsic compostability deriving from application of the UNI EN ISO 14855 standard.

Claims

1. A trimmer, line 1 for a trimmer 2 comprising a polymer material comprising:

from 50 to 79 % polyamide 6 added with plasticizer in a percentage in the range between 5 and 20%;

from 20 to 49 % copolyamide 6/66;

from 0.5 to 20 % biodegradability promoting additive; and

from 0 to 10 % dye.

2. The trimmer line according to claim 1, characterized in that said polyamide 6 is present in amounts in the range between 60 and 75 wt%.

3. The trimmer line according to claim 1 or 2, characterized in that said copolyamide 6/66 is present in amounts in the range between 25 and 35 wt%.

4. The trimmer line according to claim 1 or 2, characterized in that said biodegradability promoting additive is added in an amount in the range between 0.5 and 5 %, for example 1 %.

5. The trimmer line according to any of the preceding claims, characterised in that the dye is added in an amount in the range between 0 and 5 wt%.

6. The trimmer line according.R to any of the preceding claims, characterised in that said plasticiser is added in an amount in the range between 9 and 12 %.

7. The trimmer line according to any of the preceding claims, characterised in that said plasticiser is caprolactam.

8. The trimmer line according to any of claims 1 to 6, characterised in- that said plasticiser is butylbenzen sulphonamide .

9. The trimmer line according to any of the preceding claims, characterised in that oxodegradable additives are used as biodegradability promoting additive .

10. The trimmer line according to any of claims 1 to 8, characterised in that additives comprising active ingredients of organoleptic-organic cultured colloids, natural fibre are used as biodegradability promoting additive.

11. The trimmer line according to any of claims 1 to 8, characterised in that ECM Masterbatch Pellets^® is used as biodegradability promoting additive.

12. The trimmer line according to any of the preceding claims, characterised in that the dye is a masterbach dye.

13. A polymer material comprising:

from 20 to 49 % copolyamide 6/66;

from 0.5 to 20 % biodegradability promoting additive; and

from 0 to 10 % dye.

14. The polymer material according to any of claims 2 to 12.