MXPA97008672A - Formulation of heavy metal-free polyvinyl chloride compounds, for automotive primary wire isolation of delg wall - Google Patents

Abstract

The invention comprises a formulation based on compounds of Vinyl Chloride (PVC), particularly to compounds with high mechanical resistance, especially in regard to abrasion and that in its composition does not contain stabilizers based on heavy metals, for isolation of Thin-walled automotive primary cable and a procedure for preparing said formulation

Description

FORMULATION OF POLYVINYL CHLORIDE COMPOUNDS FREE OF HEAVY METALS FOR CABLE ISOLATION PRIMARY AUTOMOTIVE OF THIN WALL BACKGROUND OF THE INVENTION The invention comprises a formulation based on compounds of Vinyl Chloride (PVC), particularly to compounds with high mechanical resistance, especially in regard to abrasion and that in its composition does not contain stabilizers based on heavy metals Vinyl polychloride, referred to hereinafter as PVC. It is known in the art as a product that is widely used in insulation and electrical conductor cable covers due to its low cost and easy to obtain, as well as its mechanical properties, its chemical resistance and the environment also for its dielectric properties.

The use of PVC for this type of invention is always used with the addition of plasticizing agents to remove its natural stiffness and give it the desired flexibility, the addition of other additive agents such as thermal stabilizers, lubricants, pigments, fillers, impact modifiers and flame retardants that are included in the formulation to obtain the PVC with the desired properties.

PVC by itself is thermally unstable, decomposing at a temperature close to 150 ° C releasing HCl producing unsaturation sites in the polymer which leads to the crosslinking or crosslinking of the chains and their breaking, resulting in the degradation of polymer properties . As the PVC decomposes the resin changes color and becomes rigid and brittle.

To improve thermal stability, stabilizers are always used for PVC compounds. The most commonly used stabilizers are metal salts of organic acids and phenols, or inorganic, organometallic, epoxy and phosphite compounds. In the case of compounds designed for the use of automotive primary cable insulation PACKARD ELECTRIC ES M 2397 specification, which mentions that the compounds used for the manufacture of the cables with the thin wall design according to the specification for cables ES M 3089 must be lead free.

The current and future automotive industry is being affected by the following factors: The environmental legislation that requires the reduction of the environmental impact of current vehicles both in the emissions they produce as well as in their construction. Increase in economy, safety, luxury and comfort offered by current vehicles.

These requirements have forced vehicle manufacturers to make changes in both the materials involved in the manufacture of the vehicles and the performance of the same in use.

The first modification consisted in the elimination of the harmful materials found in the polymeric compounds, among which is the PVC, which, for both electric and cost advantages, had traditionally used lead.

With the intention of reducing the environmental impact, improvements have been made to internal combustion engines to optimize fuel consumption. On the other hand, vehicle designs have been made with smaller dimensions and weights, as a result of which space has been reduced. different compartments having less space for devices and their connection harnesses, which have also increased in number to improve safety and luxury. For these reasons the car manufacturers have modified the designs of the cables, decreasing the thicknesses of the walls of the insulators to reduce their weight and diameter in order that in the same space they can increase the number of circuits, these reductions in the Thickness of the walls of the cables must not present a deterioration of their performance.

DESCRIPTION OF THE INVENTION One of the different ways to cover the requirements mentioned in the previous chapter could be the use of a PVC resin with a high molecular weight which gives the compounds an increase in their mechanical properties, however, due to the scarcity of this type of resins. high molecular weight in the national trade it is preferred to use another substitute polymer to reinforce the PVC both in its mechanical properties, such as abrasion, and puncture etc.

On the other hand, given the requirements of resistance to fracture at low temperature and at the same time maintain its properties when exposed to high temperature, the phthalic type plasticiser co-ester of 11 and 9 carbon atoms was chosen, which as a co-ester has a Freezing point of -60 ° C, and has a low volatility at high temperatures.

Among the main characteristics that the cable must cover, the following are mentioned: • Stress strain at Rupture • Elongation at Rupture • Resistance to temperature (Aging in furnace) • Resistance to the different fluids in which the cables are exposed: gasoline; engine oil, transmission oil, hydraulic fluid, brake fluid, antifreeze fluid, battery electrolyte.

• Resistance to abrasion • Resistance to fracture at low temperature. • Puncture resistance (resistance to crushing) • Flame resistance The compounds with high resistance to puncture and automotive fluids of the present invention are based on a mixture of PVC or other homologous resin with a series of additive components, the amounts of the components of the formulation are expressed in parts by one hundred resin or additional resins.

All the components that make up the formulation are certified quality materials according to the following information: a PVC RESIN 250, Homopolymer type PVC resin with a K value of 70 that corresponds to a resin of viscosity and average molecular weight, PVC Chemical Abstracts Registry No. 9002-86-2. b SYNPRON 1890, Zinc-based stabilizer with ORTHANE 455-300, ester-type thermoplastic polyurethane resin. d Antimony trioxide, a flame retardant with a Chemical Abstracts record Registry No. 01309-64-4. Precipitated calcium carbonate, chemical Abstracts Registry No. 1317-65-3 f HI-SIL 233, Precipitated colloidal amorphous silica, Chemical Abstract Registry No. 112926-00-8 g PALATINOL 11 9p Linear phthalic plasticizer co-ester of 11 and 9 carbon atoms. h PALAMOLL 652, adipic polymeric plasticizer. / IRGANOX 1076, Octadecyl-3,5-diterbutyl-4-hydroxyhydrocinnamate, having a Chemical Abstracts Registry No. 2082-79-3. and Calcium stearate a lubricant with the following chemical register Absíracts Registry No. 1592-23-0. k POLYETHYLENE WAX AC-629, Homopolymer of oxidized polyethylene, with the registry of Chemical Abstract Registry No. 9002-88-4.

In PVC-based thermoplastic materials, lead stabilizers such as dibasic lead phthalate and tribasic lead sulfate are frequently used as thermal stabilizers for electric cables, however for compounds designed for use in cable insulation automotive and Zinc stabilizers have been used due to the requirements of car manufacturers, although other types of stabilizers can be used, among which are barium, cadmium cadmium or mixtures thereof, such as the MARK OHM, which is a barium cadmium soap. Similarly, other antioxidants besides IRGANOX 1076 can be used among those found in TOPANOL CA, and phenolics such as Bisphenol A.

A large number of lubricants can be used apart from calcium stearate, among which are stearic acid, paraffinic and polyethylene waxes such as AC 629 A or a mixture thereof.

As mentioned above, co-ester type plasticizers have been chosen for their low volatility at high temperature and low freezing point, however depending on the final requirements of the cable other plasticizers of another type can be used.

Next, the formulation object of the invention is described in its preferred composition defined in qualitative and quantitative terms.

Polyvinyl chloride as the PRIMEX 250 resin, in amounts ranging from 60 parts to 100 parts, preferably from 75 to 100 parts per hundred resin.

At least one thermal stabilizer used in PVC compounds for use in automotive cables such as SYNPRON 1890, in amounts ranging from 1 parts to 6 parts per hundred resin, preferably from 3 to 4 parts per hundred resin.

At least one effective anti-oxidant for PVC-based thermoplastic materials such as IRGANOX 1076 or similar, in a total amount of 0.2 to 2.0 parts per hundred resin.

At least one effective lubricant for PVC-based thermoplastic materials such as calcium stearate and / or the like or mixture, adding it in a total amount ranging from 0.15 to 2.0 parts per hundred resin.

A charge of precipitated calcium carbonate and a colloidal silica filler in amounts ranging from 10 to 50 parts per hundred resin, preferably from 15 to 25 parts per hundred resin.

A retardant based on antimony trioxide in amounts ranging from 2 to 8 parts per hundred resin, preferably in amounts of 3 to 6 parts per hundred resin.

A urethane polymer having compatibility with PVC resin to improve its mechanical properties.

Procedure to prepare the formulation of halogenated polyvinyl free of heavy metals for insulation of thin-walled automotive type primary cables with excellent resistance to abrasion.

The compound according to the invention is prepared using the steps that are individually known to those having experience in the manufacture of compounds, in which a high intensity cutting mixer is used for the manufacture of the compound up to the step of obtaining the mixture dry (dry blend) and subsequently can be plasticized either through the following processes: 1. - An internal mixer of the Banbury type for a time and a certain temperature unloading the compound on a roller mill obtaining strips of the compound that can be cut into granules. 2 Unloading the dry mix in a continuous laminating and granulating machine or another type of compound processing machine.

Initially the plasticizers are weighed and added to the PVC resin together with the stabilizer in a high intensity mixer which does not require additional heating, the intensive mixer is worked until the formation of the dry blend (dry blend) is added and the loads and lubricants for two minutes so that the dry mix is finally discharged in a water jacket cooler to reduce its temperature once the temperature of the dry mix is reduced, either the compound is passed to the extruder granulator which plasticizes the mixture and disperses and finally granulates the compound, or it is passed to the internal Banbury mixer in which it is worked until reaching a temperature of 160 ° C, unloading the compound on a roller mill where a band is obtained which is finely granulated to feed the extrusion machine Experimentation The formulation of the composition of this invention optimized for use in cables fiber optic cable was prepared in accordance as previously mentioned.

The cable obtained according to the formulation of this invention was subjected to the tests marked in the PACKARD ELECTRIC ES M 2397 standards, carrying out the evaluations as a compound and the standards PACKARD ELECTRIC ES M 3089 evaluating the compound as cable, obtaining the approval for its use as an insulator of the cables supplied for PACKARD ELECTRIC / GENERAL MOTORS, using the tests: ES M 2397 Evaluation of plate properties ES M 3089 Evaluation of cable properties.

Having described the invention was considered a novelty and therefore the content is claimed in the following:

Claims (5)

1. R E I V I N D I C A C I O N S a formulation of polyvinyl chloride compounds, free of heavy metals, for insulation of thin-walled automotive primary cable, characterized by a mixture of: polyvinyl chloride (PVC) resin in a ratio of 60 parts to 100 parts by weight; a zinc-based thermal stabilizing agent in a weight ratio of 1 to 6 parts per 100 parts of PVC; An octadecyl-3,5-diterbutyl-4-hydroxyhydrocinnamate antioxidant agent in a ratio of 0.2 to 2.0 parts by weight per 100 parts of PVC, a lubricant based on calcium stearate in a ratio of 0.15 to 2.0 parts per 100 of PVC; mixture of precipitated calcium carbonate and colloidal silica in amounts from 10 to 50 parts per 100 of PVC; an antimony trioxide retarding agent in a ratio from 2 to 8 parts per 100 of PVC; Urethane polymer compatible with PVC up to 100% complement.
2. The formulation of polyvinyl chloride compounds, free of heavy metals, of the clause, characterized in that a zinc stabilizing agent of 1 to 6 parts per 100 of PVC is preferably used.
3. 3. - The formulation of polyvinyl chloride compounds, free of heavy metals, of clause 1, characterized in that it uses a mixture of precipitated calcium carbonate and a load of colloidal silica in a preferential ratio of 15 to 25 parts per 100 of PVC .
4. 4. - The formulation of polyvinyl chloride compounds, free of heavy metals, of clause 1, characterized in that it employs an antimony trioxide retarding agent in a preferential ratio of 3 to 6 parts per 100 of PVC
5. 5. - Process for preparing the halogen-free heavy metal polyvinyl formulation of clause 1, characterized in that the plasticizers are mixed with the polyvinyl chloride resin in a high intensity mixer; then, the stabilizing agent is included in the indicated proportions until said dry mixture is formed; the carbonate and silica gel fillers are added together with the lubricating agents during a stirring time of at least two minutes; The powder product is discharged to a cooler to lower the temperature, the product obtained is plasticized and granulated at temperatures close to 160 ° C and then extruded as an automotive type primary cable insulation material. E X T R A C T O The invention comprises a formulation based on compounds d Polyvinyl chloride (PVC), particularly to compounds with high mechanical resistance especially as regards abrasion and that in its composition does not contain stabilizers based on heavy metals, for isolation of thin-walled automotive primary cable, and to a process for preparing said formulation.