IT201900015135A1 - BIOLOGICAL AND BIODEGRADABLE FLEXIBLE HOSE FOR THE TRANSPORT OF FLUIDS - Google Patents

Description

BIOLOGICAL AND BIODEGRADABLE FLEXIBLE HOSE FOR THE TRANSPORT OF FLUIDS

DESCRIPTION

Field of application

The present invention relates to the technical field of flexible pipes, for example irrigation pipes, and in particular concerns the use of a bio-based and biodegradable polymeric compound for the production of flexible pipes, an assembly that includes such pipe, as well as a flexible tube made with this compound.

Definitions

In the present text, the term "% by weight" referring to one or more components in a composition of interest indicates the percentage of the dry weight of such one or more components with respect to the total dry weight of the composition.

In the present text, the term "matrix" and its derivatives refers to a polymeric material capable of providing the molecular structure of the finished product.

In the present text, the term "plasticizer" and its derivatives means a compound or mixture of compounds that can increase the flexibility, processability and extension of the polymer in which it is incorporated. A plasticizing agent can reduce the viscosity of the mixture, lower the second order phase transition temperatures and the elastic modulus of the product.

In the present text, the term "stabilizing agent" and its derivatives means a compound or a mixture of compounds which can for example prevent the hydrolytic cleavage of the ester bonds of the PLA to form a more stable intermediate compound.

In the present text, the term "antioxidant agent" and its derivatives means a compound or a mixture of compounds capable of inhibiting thermo-oxidative and photo-oxidative reactions by reducing and / or preventing, for example, the formation of radical reactions and free radicals.

In the present text, the term "filler" and its derivatives refer to solid materials in particles or fibrous, substantially chemically inert, with the function of fillers.

In the present text, the term "additive" and its derivatives means a substance which, added to a compound, improves one or more characteristics.

State of the art

Flexible pipes for transporting fluids, in particular liquids, are known. Such pipes are generally made of plasticized PVC or elastomer. Where appropriate, the tubes themselves are reinforced with polymeric threads, usually polyester.

A recognized drawback of these hoses is the high environmental impact of the same, both in terms of materials used for the construction and disposal of the finished product.

On the other hand, bio-based, biodegradable and disintegratable compounds are known. These compounds find their main use in the production of packaging for the production of handbags and cutlery.

This is due to the stiffness of these compounds, which allows them to be used for thicknesses generally in the order of 100 - 150 microns.

Presentation of the invention

The object of the present invention is to obviate the drawbacks illustrated above by providing a flexible tube with a reduced environmental impact.

This purpose, as well as others that will be clearer later, is achieved by the use of a polymeric compound in accordance with what is described and / or claimed herein.

In general, the flexible pipes according to the present invention may be useful for the transport of any fluid, in particular any liquid.

This flexible tube can be single-layer or multi-layer, and can be reinforced or not.

In particular, the flexible hose may be a reinforced multilayer irrigation hose or garden hose for the transport of drinking water.

The flexible tube, whether single-layer, multilayer or reinforced multilayer, may have a maximum overall thickness of at least 500 microns, preferably at least 650 microns, more preferably at least 800 microns. It is evident that this thickness affects the biodegradability and disintegration of the flexible hose.

The polymer compound consists of:

(A) from 30% by weight to 70% by weight of a matrix, preferably selected from: PLA, PHA, PBS, PE of vegetable origin, PTT, PPP;

(B) 20% by weight to 65% by weight of at least one plasticizer;

(C) 0.1% by weight to 2.5% by weight of at least one stabilizing agent;

(D) 0.1% by weight to 1% by weight of at least one antioxidant agent;

(E) from 0 to 5% by weight of one or more fillers;

(F) from 0 to 2% by weight of one or more pigmenting agents;

(G) from 0% to 10% by weight of at least one further additive.

Conveniently, the polymeric compound can be:

- at least 80% bio-based, and preferably at least 90%, this characteristic being measured according to ASTM D6866;

- biodegradable according to the conditions established by the ISO 14855 standard for industrial compostability, ie it can essentially biodegrade in a maximum time of 6 months at a temperature of 58 ° C ± 2 ° C;

- it can be disintegrated according to the conditions established by the ISO 16929 standard for industrial compostability, ie it can essentially disintegrate in a maximum time of 3 months at a temperature of 40 - 60 ° C.

For this purpose, all the components from (A) to (D) above and, if present, from (E) to (G) must have characteristics such as to allow the compound to satisfy the above tests.

All the components from (A) to (D) above and, if present, from (E) to (G), will also have such characteristics and will be in a weight ratio such that the polymer compound has a measured Shore A hardness according to UNI EN ISO 868 between 55 Sh A and 90 Sh A, and preferably between 65 ShA and 80 ShA.

Furthermore, the above components can be selected so that the polymeric compound has:

- a tensile strength according to ASTM D 638 between 5 MPa and 30 MPa; and / or

- an elongation at break according to ASTM D 638 between 400% and 1000%. The above characteristics make the polymeric compound particularly suitable for making flexible pipes. In particular, for this purpose the weight ratio between the matrix and the plasticizer is important.

In the case of matrix (A) based on PLA, this weight ratio can be between 1: 1.2 and 0.4: 1, and preferably between 1: 1.1 and 0.9: 1.

Advantageously, moreover, the above compound may include a main plasticizer, for example glycerin, citrates or succinates, and optionally a secondary plasticizer, for example epoxidized soybean oil.

In particular, the glycerin can be of animal or vegetable derivation or it can be of synthetic derivation.

The main plasticizer can be between 20% by weight and 60% by weight, while the secondary plasticizer can be between 0% and 5% by weight.

Conveniently, the stabilizing agent can be chosen from the carbodiimides or the tris (nonyl-1-phenyl) phosphite.

Advantageously, the antioxidant agent can be chosen from ascorbyl palmitate or butylated hydroxyanisole or butylated hydroxytoluene.

Conveniently, the filler can be talc or calcium carbonate.

Advantageously, the pigmenting agent can be chosen from natural food dyes.

The hose according to the present invention may include one or more layers, and may or may not be reinforced. In the case of multilayer pipes, one or more of the layers can be made in the compound described above.

For example, in FIG. 1 shows a multilayer flexible tube 1 for transporting liquids, which may have a first layer 2 in contact with the fluid to be transported, a second outer layer 3 that can be gripped by a user and at least one reinforcing textile layer 4 interposed between the first layer 2 and second layer 3. The latter can both be made in the compound described above.

Conveniently, the textile layer 4 can be made using threads in bio-based material, biodegradable according to the conditions established by the ISO 14855 standard for industrial compostability and disintegrating according to the conditions established by the ISO 16929 standard for industrial compostability.

For example, the threads could be PLA.

The aforementioned tube can be made in a manner known per se, with the inner and outer layers 2 and 3 made by extrusion and the textile layer 4 by means of a special processing station, for example a knitting, coiling or screening station.

Conveniently, pipe 1 can be coupled with a pair of fittings made of a bio-based material, biodegradable according to the conditions established by the ISO 14855 standard for industrial compostability and disintegrating according to the conditions established by the ISO 16929 standard for industrial compostability. For example, this material could be PLA.

The invention will be described in more detail with reference to the following examples which, in any case, are not intended to limit the scope of protection of the invention.

Examples

Example 1 - preparation

Some examples of compounds have been prepared. The raw materials used were:

(A) matrix: bio-based PLA marketed by NatureWorks LLC

(B) plasticizing agents: Glycerol marketed by Cargill;

Tribultil Citrate marketed by Wego Chemical Group;

Epoxidized soybean oil marketed by AMIK PLASTIFICANTI SRL and KIMASOL DB.

(C) stabilizing agent: Carbodiimides marketed by LANXESS Deutschland GmbH;

Tris (nonyl-1-phenyl) phosphite marketed by Dover Chemical Corporation;

(D) antioxidant agent: Ascorbyl palmitate marketed by Evonik;

(E) Butylated hydroxyanisole marketed by Eastman;

Butylated hydroxytoluene marketed by Eastman;

(F) filler: Talc marketed by Omya;

Calcium carbonate marketed by Omya;

(G) pigment: Natural food coloring marketed by BIO-FED (Branch of AKRO-PLASTIC GmbH).

The formulations, which were prepared using a twin screw mixer / extruder, are shown in the following table 1.

TABLE 1

All three formulations are 100% bio-based according to the ASTM D6866 standard, biodegradable according to the conditions established by the ISO 14855 standard for industrial compostability and disintegrating according to the conditions established by the ISO 16929 standard for industrial compostability.

Example 2

For all three of the above compounds, the Shore hardness, tensile strength and elongation at break were measured. The results are in the following table 2.

TABLE 2

Therefore, all three of the above compounds are suitable for making one or more layers of a flexible hose.

Claims (14)

CLAIMS 1. The use of a polymeric compound for the construction of a flexible hose for the transport of fluids, in particular liquids, in which the polymeric compound consists of: (A) from 30% by weight to 70% by weight of a matrix; (B) 20% by weight to 65% by weight of at least one plasticizer; (C) 0.1% by weight to 2.5% by weight of at least one stabilizing agent; (D) 0.1% by weight to 1% by weight of at least one antioxidant agent; (E) from 0 to 5% by weight of one or more fillers; (F) from 0 to 2% by weight of one or more pigmenting agents; (G) from 0% to 10% by weight of at least one further additive; in which the% by weight are calculated with respect to the total weight of the polymeric compound; in which the polymeric compound is at least 80% bio-based, and preferably at least 90%, according to ASTM D6866; in which the compound is biodegradable according to the conditions established by the ISO 14855 standard for industrial compostability; in which the compound can be disintegrated according to the conditions established by the ISO 16929 standard for industrial compostability; in which the polymeric compound has a Shore A hardness measured according to UNI EN ISO 868 between 55 Sh A and 90 Sh A, and preferably between 65 ShA and 80 ShA. Use according to claim 1, wherein the polymeric compound has a tensile strength according to ASTM D 638 comprised between 5 MPa and 30 MPa. Use according to claim 1 or 2, wherein the polymeric compound exhibits an elongation at break according to ASTM D 638 comprised between 400% and 1000%. Use according to claim 1, 2 or 3, wherein the flexible tube has an overall thickness of at least 500 microns, preferably at least 650 microns, more preferably at least 800 microns. Use according to one or more of the preceding claims, wherein said matrix is based on a compound selected from: PLA, PHA, PBS, PE of vegetable origin, PTT, PPP. Use according to one or more of the preceding claims, wherein said matrix (A) is based on PLA, the weight ratio between said matrix (A) and said at least one plasticizer being between 1: 1.2 and 0, 4: 1, and is preferably between 1: 1.1 and 0.9: 1. Use according to the preceding claim, wherein said one or more plasticizing agents include a main plasticizer and a secondary plasticizer, said main plasticizer being between 20% by weight and 60% by weight, said secondary plasticizer being between 0 and 5% by weight, the% by weight being calculated with respect to the total weight of the compound. Use according to the preceding claim, wherein said main plasticizer is glycerin, said secondary plasticizer being epoxidized soybean oil. 9. A flexible tube having at least a first layer made of the compound claimed in one or more of the preceding claims. 10. Flexible pipe according to the preceding claim, wherein said at least one first layer is in contact with the fluid to be transported, the flexible pipe further comprising at least a second external layer capable of being gripped by a user made of said polymeric compound, the pipe flexible, further comprising at least one textile reinforcement layer interposed between said at least one first layer and at least one second layer. 11. Hose according to the preceding claim, in which said at least one textile layer is made of threads in bio-based material, biodegradable according to the conditions established by the ISO 14855 standard for industrial compostability and disintegrating according to the conditions established by the ISO 16929 standard for the industrial compostability. 12. Tube according to the preceding claim, wherein said wires are PLA wires. 13. A tube assembly comprising: - at least one tube in accordance with one or more of claims 5 to 8; - at least one pair of fittings made of a bio-based material, biodegradable according to the conditions established by the ISO 14855 standard for industrial compostability and disintegrating according to the conditions established by the ISO 16929 standard for industrial compostability. 14. An assembly according to the preceding claim, wherein said material is PLA.