SE416135B - SILICATE MIXED RESIN COMPOSITION MATERIAL AND PROCEDURE FOR ITS MANUFACTURING - Google Patents

Description

vsozsso-s 2 is exposed to the processing temperatures. This increase in strength can also be achieved by exposing the mixture to higher temperatures for shorter periods of time. An amount of 1-36 parts by weight of silicate filler per 9 parts by weight of polyolefin resin gives composite materials with particularly suitable properties, while a weight ratio filler to resin of about 2: 5 - 5: 2 normally gives optimal results for silicates such as mica flakes and a weight ratio of about 1 : 10 - 4:10 is advantageous for silicate such as glass fibers. Preferred silicate materials are mica, especially mica flakes.

Polyolefin resins suitable for the invention are well known, commercially available materials which are intended for use in molding (such as injection molding, compression molding) and other melt molding processes (such as extrusion, stamping).

Of these commercial resins, those prepared from monomers comprising olefinic hydrocarbons such as ethylene, propylene and butene-1 can provide composite materials with excellent properties as well as economic benefits. Particularly suitable in this respect are resins which comprise polyethylene or polypropylene or copolymers of ethylene and / or propylene as well as mixtures of any of these compounds.

In this context, the term polyolefin resin refers to any of the above resins which are normally formed during melting and which are produced from monomers comprising olefinic monomers, in particular monomers consisting of aliphatic hydrocarbon monomers and preferably predominantly (by weight) 1 olefin hydrocarbons such as ethylene, propylene, butene-1 and 4-methylpentene-1. Such polyolefin resins preferably have a larger proportion of the resin in the composite material (eg 60% by weight or more). Upon melting, the polyolefin resin wets the surface of the silicate filler in the mixtures. By a hitherto unclear mechanism, it is assumed that wetting and bonding are favored when the present additives are added to the mixtures.

Propylene resins are particularly suitable according to the invention, especially those with internal viscosities above 1.5, preferably about 2.0 - 2.6, for process engineering reasons, but those with higher internal viscosity can also be used to advantage. The propylene resins may comprise propylene homopolymers or propylene copolymers or mixtures thereof, the copolymers normally comprising at least about 75 mol% of propylene and up to 25 mol% of other monomers, such as ethylene and butene-1. Suitable propylene resins are those propylene homopolymers or copolymers normally made with stereospecific catalysts. These propylene resins are suitably in flake or powder form and pass through a sieve with a mesh size of 0.84 mm (20 mesh), preferably 0.25 mm (60 mesh), and although present propylene resins are substantially retained by sieve with a mesh size 0.04 mm (325 mesh), even smaller sizes can be used according to the invention. Ethylene resins, such as polyethylene homopolymers or ethylene copolymers prepared with other aliphatic olefinic hydrocarbons, such as propylene, butene-1 and hexene-1, are also particularly suitable.

Silicate fillers are available commercially. Of the silicate fillers commonly used, synthetic glass fibers and natural mica as well as other naturally occurring minerals, such as talc, are particularly suitable in this context. These silicate fillers usually include silicon, acids and one or more metals, eg Mg, Al, Na. Fillers of a certain shape, such as glass flakes, fibers and mica flakes, have the advantage that they provide a greater structural whole for the polyolefin resin composite materials and such composite materials can be particularly advantageous according to the invention. Glass fibers with high ratios of length to diameters, eg 30: 1 or higher, as well as flakes with at least such ratios are suitable for the composite materials which have the highest strength. Other silicate fillers are magnesium silicate, calcium silicates, vollastonite, attapulgite, silicate clays as well as other materials described in U.S. Pat. No. 3,951,680. Silicate fillers which do not contain forms of asbestos are preferred.

It is advantageous if the silicate filler, such as mica, has not been subjected to any major chemical surface treatment for use according to the invention. The additives of the invention are normally inexpensive and the need for more expensive surface treatments, such as with silane compounds, can be eliminated or reduced. Furthermore, it is desirable that the additive interfere as little as possible with the silicate surface and the polyolefin resin.

Mica fillers can usually be described as materials derived from aluminum silicate minerals, which are split into thin layers.

Commercially available fillers, which mainly include muscovite, biotite and / or phlogopite mica (eg Suzorite Mica from Marietta Resources International) and mica fillers, which mainly comprise phlogopite mica, appear to be most suitable at present.

Mixtures of mica as well as with other silicate fillers can also be used. Mica flakes, especially those comprising mainly phlogopite mica, having an aspect ratio (i.e. diameter to thickness) of at least about 30 (or more preferably at least about 60 to minimize refractive effects during processing) and up to 200 or more are preferably used. . Mica flakes, son1 retained on a screen with a mesh size of 0.5 mm (100 mesh), preferably 0.25 mm (60 mesh), are normally desirable, but mica passing through screens with a mesh size of 0.04 mm (325 mesh) can also be used.

Mica flakes, which can substantially pass through a screen with a mesh size of 0.84 mm (20 mesh), are preferred for process engineering reasons.

In general, glass flakes and fibers of such dimensions are particularly suitable here. Although various methods of producing extremely delaminated mica flakes are used in the mineral industry, such methods are preferred where wet grinding is not used. Dry delamination methods are especially preferred, where ore, which to some extent contains the various mica forms, is excavated and crushed into lumps for transport reasons. The size of these lumps is further reduced by grinding with hammer mills to rid the units (or the individual_glaze crystals) of other mineral contaminants.

The crystals are delaminated in such a preferred drying process between counter-rotating drums, which exert high shear forces.

The degree of delamination, and consequently the lateral ratio of the mica flakes obtained, depends on the tolerance set between the counter-rotating drums. The delaminated flakes are then separated from other mineral contaminants by vibration and / or air classification methods in which the purified mica is further sorted by particle size via conventional sieving methods.

When the mica is prepared in this way, the mica surfaces become relatively free from larger amounts of adsorbed substances (such as moisture from water grinding), which can interfere with the additives described for the invention.

The additive which increases the adhesion of the silicate filler, such as mica, and the polyolefin resin, is used in minor amounts, (eg 0.05-10%, preferably between about 0.5 - 5%), based on the weight of the combined silicate filler and the polyolefin resin. which amounts are sufficient to increase the strength of the composite material. Often a sufficient amount of the additive is less than the amount of silicate filler if the weight is calculated. Thus, for example, resinous chlorinated waxes are used in less than about 3% by weight of the total weight of silicate filler and polyolefin resin. 7803580-5 The ASTM (D-790) flexural strength ("Flexural Yield Strength" according to ASTN D-790) is a suitable measure of the strength of the composite material.

Other signs of increased strength are seen, for example, in increased tensile strength, bending strength and heat resistance temperature as well as in the reduction of the press shrinkage.

The chlorinated aliphatic compounds, which are preferred according to the invention, have a molecular weight (number average molecular weight) between 500 and 10,000 (more preferably between 800 - 5,000) and a chlorine content of 5 to 80% by weight.

High weight contents (eg about 60 - 80%) chlorine are suitable for chlorinated saturated hydrocarbons, such as chlorinated paraffin waxes. Lower weight contents of chlorine (eg 5 - 50) are particularly suitable if one has additional polarity (eg carboxyl groups) or unsaturation in the chlorinated aliphatic compounds. Lower molecular weight, eg 250, can be used especially when you have a high weight content of chlorine.

Examples of additives which include chlorinated aliphatic compounds are chlorinated hydrocarbons, such as resinous chlorinated paraffin waxes (e.g. those marketed as Chlorowax [Diamond Shamrockl, Chlorochek [Keil Chemical, belonging to Perro Chemical] and Chlorez) [ ). Resinous chlorinated waxes having molecular weights of about 800-1200 are preferred, such as, for example, Chlorowax 70. In According to a preferred embodiment for the production of composite materials according to the invention, finely divided polyolefin resin (in powder or flake form), silicate flakes (eg mica) are mixed or fibers and a powdered additive comprising chlorinated aliphatic compounds by stirring (preferably non-intensive) and then extruding the mixture by vacuum blowing.

The extruder has at one end a heated tube which prolongs the time that the passing melt is exposed to high temperature. For propylene resin, silicate fillers comprising, for example, logopit mica, and resinous chlorinated paraffin waxes, a total time after melting (ie melting residence time) of about 5-10 minutes at about 190-210 ° C before the melt is cooled is preferred.

Subsequent heating such as expiration and drying can also be used to contribute to this residence time. The melt can then be formed by pressing, but other manufacturing methods can be used.

In another preferred embodiment, the silicate (eg mica) is first mixed with the additive comprising one or more chlorinated aliphatic compounds to obtain a coating on the silicate particles (eg flakes such as mica flakes or fibers). Resinous chlorinated aliphatic hydrocarbons, such as chlorinated paraffin wax, are suitably melted (in up to about 15% by weight or more preferably up to about 2% by weight of the silicate) on the silicate at a preferably high temperature (eg 150 ° C) but preferably below temperature, which would cause severe decomposition and degradation of the reinforcing effect which the additive gives rise to. This melt coating is normally carried out with gentle agitation of the silicate particles and the additive in order to obtain an even coating and as low a breakdown of the formed particles as possible. Preferably, the silicate filler, such as mica, is dried prior to the melt coating with the additive. The melt coating can suitably be carried out in less than 1 hour, normally less than 15 minutes, depending on such factors as mixing equipment, mixing conditions and temperature. the coating of the silicate has the advantage that you get much more uniform mixtures than is the case when you mix the components separately. The coated silicate is further suitably mixed by mixing with the polyolefin resin to form a dry powder mixture for further processing.

Temperatures between about 170 and 300 ° C are generally suitable during the above preferred mixing procedures with the polyolefin resin. Higher temperatures in this range, eg 220 ° C or higher, usually require less time for the optimum properties to develop, while lower temperatures require longer periods. The additives of the present invention advantageously lead to stable, later obtained mechanical properties at ordinary melting temperatures for long periods, for example 30 minutes or longer. It is normally desirable to have a period between about one (1) and 30 minutes at the melting temperature and more preferably between 5 and 15 minutes. Subsequent steps, such as molding at the melting conditions, can contribute to this melting residence time. After mixing, the melt, which has suitably remained for a long period at the melting temperature, can be transferred to a cooling zone and then cut (eg in a grinder) into particles suitable for forming processes. Alternatively, the melt can be passed directly to a forming step. If the molding is by injection molding, this is suitably done at about 21-62 MPa at temperatures, vsossso-s of about 190 - 2010 ° C in molds, which are kept at about 30 - 70 ° C.

Other molding methods, such as extrusion, compression molding or blowing or stamping and the like can be used. Furthermore, forming processes can be used to maintain such time and temperature as are sufficient to increase the strength of the composite material. Furthermore, one can also take advantage of the invention in the manufacture of rods, sheets, tubes and films.

The compositions of the invention may contain combinations of fillers, such as mica with glass fibers or talc as well as minor amounts of additives (eg stabilizers, pigments, lubricants and the like), which are conventionally included in the manufacture of composite materials. Oxides of alkaline earth metals (eg MgO, CaO) can be present, for example, in amounts by weight up to 5% of the weight of the composite material and they are advantageously used to absorb gases coming from trapped moisture or decomposition of additives formed during mixing or the melt-forming processes, which take place at high temperature.

The following examples are intended to illustrate the invention without limiting it, and as will be appreciated by those skilled in the art, many modifications of these examples may be made within the scope of the invention.

All parts refer to parts by weight, all temperature indications refer to degrees Celsius and all tests refer to standard ASTM tests unless otherwise specifically stated.

EXAMPLE 1 In this example, composite material 1 standard ASTM samples were formed from formulations of varying concentrations and types of polyolefin resin, silicate fillers and chlorinated aliphatic compounds.

The composite materials were prepared by dry mixing (non-intensive mixing) the resin (powder form), the silicate filler and additives comprising the chlorinated aliphatic compounds.

Then a powder mixture was added to an injection molding machine with reciprocating screw (Arburg 200U, 42 tons, 2 oz), the mixture was kept at 200 ° C for the time periods given in Table 2 and sprayed in a mold with the temperature 309C. The shot size setting is 6.3.

The composition of the composite material produced is shown in Table 1.

The properties obtained from a first set of composite materials are shown in Table 2. The composite material for ASTM testing in this first set was made after first cleaning the ivsøssso-i * _ 8 forming machine with ten shots of the individual preparations with a minüts intervals followed by shoots, taken at the intervals shown in Table 2. 7803580-5 fl momñonu dm fl uwmm> æ wwummmuwcxum fi .oomo fi ^ umo fl> v uxønmwwømøxn flfi suo .oomm w «> mo ooow ^ øwuxm> wa uwøx. H umu «moxm«> .uo fl x Nux «> m fi nu ^ xoouEmcm wøoñmwnv uo fl x Nux fl> On nu fifl swm fi w:« \ H mwæ | MI hmn «mwm fl wIwc« cuou: mao A fi mcowumcumwuu um wu III: . ~ IIIII <QIQHM ø fi wm fi oß fi øm o. ~ I oH I oH o. ~ O. ~ OH I n mAIo ~ xmseuo fi ßo wumm flfl wæ IIIIIIIIIN uwswwwm fi w IIII o.om IIII ^: w ~ sm ~ mv se «o.ø cmv w« «øø cmv v« umuxww Ecømw umuwwmwmv, ImIWNMI .. UUMNONSW oo «oo« o.on o.om I ø. ° m oo «o.om o.om nnmwe owv se m ~ .o =« @ ¶M> xw «a uwa -uxMm > m mmH fl wnnm> &: må fi smwä omv EE <æ.o cwwv «> xwmE maa umuxwm Eøcww umumwwmmv a umE« HwI: Axwñ fl ouw fi wxwuumßv Hw fl wa fifi hwummw fl wm o.om o.oo I I I I I I I ^ I.

Claims (4)

-7803580-5 15 PATENT CLAIMS Composite material, characterized in that it is prepared by a) providing a mixture comprising a melt-forming resin prepared from monomers comprising olefin hydrocarbons, mica and a strength-increasing amount, which is a smaller amount of the total weight of the resin and mica , of an additive which consists essentially of one or more chlorinated aliphatic compounds with a molecular weight in the range of about 250 - 10,000 and about 5-8 ° C>% by weight of chlorine, and b) retains the mixture as a melt for a period of up to to 30 minutes at a temperature of 170-300 ° C to improve the strength of the composite material. 2. A composite material according to claim 1, characterized in that the mica has been combined with the additive so that a coating has formed on at least a part of the mica particles. 3. A process for producing composite materials, characterized in that a) a mixture is obtained comprising a melt-forming resin prepared from monomers comprising olefin hydrocarbons, mica and a strength-increasing amount which is a smaller amount of the total weight of the resin and mica of an additive consisting essentially of one or more chlorinated aliphatic compounds having a molecular weight in the range of about 250 to 10,000 and about 5 to 80% by weight of chlorine, and b) retaining the mixture as a melt for a period of up to 30 minutes at a temperature of 170 - 300 ° C to improve the strength of the composite material. 4. A method according to claim 3, characterized in that the mica is combined with the additive so that a coating is formed on at least a part of the mica particles. STATED PUBLICATIONS: Germany 2,059,022 (cosf 29 / oz), 2,105,187 (cosf 29/02), 2,139,318 (cosf 29/02)