FR2876699A1 - Multi-use, high-strength material, useful for making articles of protective clothing, comprises a polyamide thermoplastic resin and elastomer - Google Patents

Abstract

Multi-use material (A) with high-grade physical and mechanical properties is a heated mixture of a polyamide thermoplastic resin (I) with addition of 5-15% elastomer (II).

Description

2876699 1

  The present invention relates to a multipurpose material with high physical and mechanical characteristics, particularly recommended to achieve easily, quickly, economically and safely current elements made of metal or other miscellaneous plastics.

  It is known that many articles, for example, accident protection reinforcements in shoes, protectors for elbows, knees and shins, various types of helmets, protective vests and the like are currently made from metals. or various synthetic materials.

  It is also known that some of said products, while being adapted to specific applications, are not suitable for other particular conditions. For example, safety shoes have anti-perforation soles and metal anti-crush tips; this configuration, while ensuring adequate protection of the feet, has a first disadvantage because of the heaviness and rigidity of the shoes, causing discomfort and fatigue for those who wear them for a long time at work; a second drawback is due to the fact that said shoes are not electrically insulating and are therefore not suitable in the presence of electric and / or magnetic fields; a third disadvantage is due to the fact that the realization and assembly of said metal elements in the shoes, not only are laborious and expensive, but do not prevent their oxidation, quickly rendering ineffective the required safety characteristics of the shoes, which, on the other hand, become unhygienic.

  Other examples relate to the hulls of motorcycle helmets and / or crash helmets worn by workers on construction sites; the materials currently used, such as plastics and / or high-strength carbon fibers, while being adapted and effective because of their lightness and for various forms of protection of a general nature, are in some cases fragile in their nature. they are subject to rather dry, violent and localized shocks.

  Other elements, such as protections in general for the elbows, knees and shins, are rather bulky and heavy, especially when it comes to applications in which users, and in particular athletes, must move with maximum agility.

  The object of the present invention is to eliminate, or at least minimize, the aforementioned disadvantages.

  The invention solves said problems by proposing a multi-use material consisting of a hot mix of a polyamide resin added with an elastomer, the amount of elastomer used in the mixture relative to the thermoplastic polyamide resin being between 5 and 15%.

  According to a secondary feature of the invention, the thermoplastic polyamide resin used in the mixture has a density typically between 1.00 and 1.20 g / cm3.

  The material obtained from the blend has high electrical insulation characteristics and high characteristics of elasticity and mechanical resistance to bending, impact and puncture. The advantages which derive from the invention reside essentially in the fact that, for the same physical and mechanical characteristics as the products currently known, the products obtained with the material which is the subject of the present invention prove to be easier to adapt to pre-existing objectives. - Established, much lighter, more economical and easily shaped by stamping, injection or stamping. Another advantage lies in the fact that, in addition to the aforementioned characteristics, the material according to the invention is a good electrical and thermal insulator.

  In the preferred embodiments of the invention, the material consists essentially of a thermoplastic polyamide resin having a density typically between 1.00 and 1.20 g / cm 3, added with 5 to 15 % of an elastomer having on average a density typically between 1.00 and 1.20 g / cm3, an elongation at break of 550 to 700%, a Shore A hardness of 75 to 90, a breaking strength of 40 to 50 MPa, a pull-out strength of 50 to 80 N / mm, an elongation resistance which is 20% of 2 to 3 MPa, 100% of 4 to 7 MPa and 300% of 7 at 1 1 MPa.

  In a typical example of application, the anti-perforation soles and anti-crush tips formed anatomically with arch for protective shoes were made by stamping and / or injection from a blend of thermoplastic resin polyamide and a percentage of 5 to 15% of elastomer at a temperature between 230 and 280 C, according to the invention.

  The results of the mechanical tests carried out on the elements thus obtained have largely exceeded the thresholds required by the normative criteria provided for by the laws in force concerning safety.

  More specifically, and by way of example, it has been found that the resistance to perforation of the sole of protective footwear with anti-perforation soles made in the material which is the subject of the present invention exceeded from 27 to 36 % (1 400 to 1 500 N) the required threshold of 1 100 N (current standard EN 344-1 / 92), for a nail with an area of 1 mm to a thickness of 3 mm minimum and 5 mm maximum, whereas after 1 000 000 bending cycles, maintaining the fixed heel and with flexures of more than 5 cm, the anti-perforation insert showed no permanent deformation or rupture (standards prEN ISO 20345/03, prEN ISO 20346/03 and prEN ISO 20347/03).

  Other elements were subjected to the following tests: impact resistance tests (impact energy 200 4 J), 2876699 4 compressive strength tests (compression load 0.1 kN), impact resistance tests after a chemical aging treatment (impact energy 200 4 J at temperatures of + 60 2 C and -20 2 C), impact tests after chemical aging treatment (impact energy 200 4 J) after immersion in a solution of sulfuric acid, after immersion in sodium hydroxide and after immersion in trimethylpentanol, at a temperature of 20 ° C. for 24 hours).

  All the results have perfectly met the requirements of the current standard EN 12568/98. The electrical insulation tests have likewise given satisfactory results.

  Thanks to these physical and mechanical characteristics, associated with the fact that it is essentially light, dielectric, hygienic, resistant to high and low temperatures, non-toxic and stainless, the material according to the invention can find application to improve the manufacturing as well. elements of so-called protective shoes than other elements intended for safety and accident protection measures, such as hard hats, motorcycle helmets, protections for the head, elbows, knees and shins of athletes , protective vests, face protectors or limbs following trauma, and others.

  To achieve said products, the material according to the invention can be implemented by stamping, injection, stamping, or profiling.

  The present invention has been described and illustrated according to embodiments chosen as examples without any limiting character. It is easy to understand that it will be obvious to experts in the technical field to use other thermoplastic polyamide resins added with similar elastomers without departing from the scope of the invention or its object.

Claims (10)

  1. Multi-purpose material having high physical and mechanical characteristics, characterized in that it consists of a hot mix of a thermoplastic polyamide resin added with an elastomer in a ratio of 5 to 15%.   2. Material according to claim 1 characterized in that the thermoplastic polyamide resin used in the mixture has a density typically between 1.00 and 1.20 gcm3.   3. multi-purpose material according to claim 1 characterized in that the elastomer used in the mixture has on average: a density typically between 1.00 and 1.20 gcm3, an elongation at break of 550 to 700%, a Shore A hardness of 75 to 90, a tensile strength of 40 to 50 MPa, a tensile strength of 50 to 80 N / mm, an elongation resistance of 20 to 2% to 3 MPa , at 100% from 4 to 7 MPa, at 300% from 7 to 11 MPa.   4. Material according to claim 2, characterized in that the amount of elastomer used in the mixture relative to the amount of thermoplastic polyamide resin is between 5 and 15% of the amount of resin.   5. Material according to claims 1 and 2 characterized in that the polyamide thermoplastic resin mixture containing 5 to 15% elastomer is obtained at a temperature between 230 and 280 C.   6. Material according to one of the preceding claims, characterized in that it has a resistance to perforation of the order of 1 400 to 1 500 N. 7. Material according to one of the preceding claims characterized in that, after 1 000 000 bending cycles with flexures of more than 5 cm, the test pieces have no permanent deformation or rupture.   2876699 6 8. Material according to one of the preceding claims, characterized in that it is used to produce objects having high mechanical and physical characteristics, intended to provide protection against shocks, perforations, thermal variations, electrical voltages .   9. Material according to one of the preceding claims, characterized in that it can be shaped by stamping, injection, stamping, or profiling.   10. A material according to any one of the preceding claims having high physical and mechanical characteristics.