Title of Invention

CONCENTRATES OF ADDITIVES IN THE PROCESSING OF POLYOLEFINS

Abstract

The present invention relates to a concentrate comprising (percentages by weight): A) from 40% to 95%, preferably from 50% to 95%, in particular from 60% to 80% of a composition comprising, relative to the total weight of A): 1) from 10% to 35%, preferably from 25% to 35%, more preferably from 30% to 35% of polybutene-1 having melt flow rate from 100 to 1000 g/10 min., measured at 190 °C/2.16 kg according to ASTM D1238, condition E; 2) from 90% to 65%, preferably from 75% to 65%, more preferably from 70% to 65% of polypropylene; B) from 5% to 60%, preferably from 5% to 50%, in particular from 20% to 40% .. of one or more additives selected from fillers and pigments

Full Text

"CONCENTRATES OF ADDITIVES FOR USE IN THE PROCESSING OF POLYOLEFINS" The present invention relates to concentrates comprising a mixture of polybutene-1 and polypropylene and one or more additives, particularly suitable for the bulk colorings of the polyolefins, preferably of polypropylene. The various types of processing to which the polyolefins are submitted include injection or blood moldings, and spinning. Particularly in the production of fibred of polyolefin resins, which is mainly carried out continuously, the colorings stage is a rather critical stage at present: on the one hand because of the ever smaller cross-section of the fibers, defined by the denier or diameter, according to a requirement of the fiber producers themselves, and on the other hand because of the high speeds reached in today's spinning processes. The concentrates, better known as "master batches", constitute the product that is added to the various polyolefins for the introduction of additives. The master batch thus generally consists of a mixture of one or more pigments/colorants, fillers or other additives dispersed and/or distributed at high concentrations in a polymeric carrier. Poor dispersion of the pigment in the master batch and hence of the master batch in the resin mass to be colored can give rise to unevenness in the resulting coloration and, in the case of fiber production, to low production yields overawing to frequents breakages of the filaments caused by the pigment, which is not well disaggregated. In the specific case of bulk colorings of polypropylene, which presents the problems outlined above, the commercially available formulations envisage dispersion of the pigment in the carrier, which can be the same polypropylene or alternatively polyethylene, by using waxes and dispersants such as separates or paraffin’s. The use of dispersants is necessary because the polyolefins, on account of their a polar nature, are characterized by very low affinity for (polar) organic pigments. However, the use of waxes (starts and/or paraffin’s), though unavoidable, is a disturbing element since for certain applications (e.g. extrusion of fibers their presence can be detrimental to the quality of the finished product. It is known that a critical parameter for the dispersion of the pigment in a carrier is the degree of crystalline of the latter. In fact, the colorant or pigment is unable to get between the lamellae of the crystal zones, but is inserted more easily in the amorphous zones of the carrier. In the specific case of the process of extrusion of polyolefin fibers, it is known in addition that the elongation stress is relieved in the amorphous zones during the said process: stretching of the chains in the zones that are not stiffened in a crystalline conformation permits spiking of the polymer to a degree that is proportional to the crystalline fraction of the polymer. The excess stress, i.e. that to which the amorphous zones are unable to respond, is relieved on the crystalline fraction of the polymer itself, which is thus of fundamental importance for the strength of the material, especially m the critical conditions of existing spinning processes. For example, document JP 2000178361 describes master batches for colorings plastics containing polypropylene, pigment and a polyethylene wax. Document JP 5179009 describes a modified thermoplastic master batch preparation with good disposability containing a thermoplastic, such as polyethylene granules, a liquid modifier, such as polybutene, and a second thermoplastic such as low-density polyethylene. It is therefore clear that selection of the carrier for the master batch is essential to achieve effective dispersion of the additive. . As noted above, polypropylene is also known as a carrier and in this case, to avoid considerable problems in the processes of colorings and spinning, it is necessary to use a semi crystalline polypropylene with a sufficiently high degree of hot fluidity to permit the pigment to be incorporated easily in the molten mass, but capable of withstanding high stretching forces during the spinning process. It is clear that the ratio of crystalline to amorphous inaction of the polymer acting as earner is an essential element in the formulation of the master batches for polymer fibbers. In the specific case of spinning, it is further evident that numerous factors contribute to the production of a homogeneous colored filament and that the process requirements and requirements on filament diameter (denier) mean that manufacturers must always carefully evaluate and determine the conditions of the coloration stage. Therefore a polymeric carrier is required that could be used for the production of master batches for use in the bulk colorings of polyolefins in processes involving colorants and/or pigments that are difficult to disaggregate and disperse and which, particularly in the fibber extrusion process, has the critical aspects mentioned above. The aim of the present invention is therefore to provide a carrier and hence a masterbatch for adding additives to polyolefins, whose efficacy is not greatly affected by the variability of the process conditions. Another aim of the invention is to provide a carrier and hence a master batch that can be used in spinning processes for the production of continuous yam of low denier and that therefore promotes the "dispersion" and the "dispensability" of the pigment, where the first term means the ability of the colorant and/or pigment to disaggregate into micro particles and disperse homogeneously in the carrier and the second term means the ability of the master batch containing the colorant and/or pigment, when incorporated at high concentration, to disperse homogeneously in the bulk that is to be colored, and hence the ability to disperse the colorant and/or pigment in the said bulk. The aforementioned aims have been achieved by using a composition comprising a polymer of 1-butene (called "polybutene-1" for short) and a polymer of propylene ("polypropylene"), as defined in the claims. Document US 3455871 describes the use of homo- and copolymers of 1-butene as carrier for promoting the dispersion of additives in the process of coloring of olefin polymers. However, blends with polypropylene are not cited in that document. Furthermore, document US 4960820 describes a polymer composition comprising a mixture of is tactic polybutene-1 (having a melt index between 100 and 1000 and added in an amount not greater than 10 wt.%), of polypropylene in an amount equal to at least 90 wt,% and of an additive present at a concentration between 0.1 and 1 wt.%, that can be used for the production of films characterized by good optical properties and good process ability, as well as fibers. However, that document does not describe the preparation and use of master batches for dispersing the additives. The Asphalt found, surprisingly, that by using, as carrier for the concentrates, a composition comprising polybutene-1 and polypropylene, in which the polybutene-1 is preferably present in amounts greater than or equal to 10 wt.%, the dispersion and the dispensability of the additives in the stage of blending with polyolefins are further promoted. In particular, the present invention facilitates the colorings stage in a process of extrusion of polypropylene fibbers, so that the pigment will not fail to be dispersed in the carrier and thus clog the filter positioned downstream of the extrusion head during the process of spinning of the polymer, causing a considerable increase in pressure. Without wishing to be linked to any theory, the possibility of using The binary mixture arose from the observation that polybutene-1 has structural characteristics similar to those of polypropylene. It was found that any ratio whatever between polybutene-1 and polypropylene in the carrier mixture gives an at least slight disposability of the pigment, as will be shown later, referring to the appended drawing. More particularly, the invention relates to the use of a carrier composition for the dispersion and disposability of the pigment comprising from 10% to 35% by weight of polybutene-1 and from 90% to 65% by weight of polypropylene. Even more preferably, the invention relates to the use of a carrier composition comprising 30-35% of polybutene-1 and 70-65% of polypropylene. In the case of the process of spinning of polypropylene, the invention relates to the use of a carrier comprising 25-35% by weight of polybutene-1 and 75-65% by weight of polypropylene, since it was foamed that for percentages below 25% of polybutene-1 the master batch obtained could not be regarded as a good product for fibers, while for concentrations above 35% the increase in dispensability of the pigment was negligible above all because it did not make up for the costs of the polybutene-1. The invention is suitable for the dispersion and disposability of any additive, without limitation as to the chemical category to which it belongs. It was found that the melt flow rate of polybutene-1 is a factor that can help to give good dispersion of the additive and it is assumed that high values of the melt flow rate give better dispersion of the additive in the carrier. Preferably, a melt flow rate from about 100 to 1000 g/10 min, more preferably from 100 to 400 g/10 min, proved advantageous for polybutene-1 (measured at 190°C/2.16 kg according to ASTM D1238, condition E). The polybutene-1 preferably employed for the concentrates of the present invention is a linear photopolymers that is semicrystalline and highly biostatic (having in particular an isotacticity from 96 to 99%, measured both as mummy pentads/total pentads using NMR and as quantity by weight of matter soluble in xylene at 0°C), obtained by polymerization of butene-1 with a stereo specific catalyst, and the binary mixture with polypropylene, as already noted, is described in the literature. In the case when a copolymer of butene-1 is used, the isotacticity index can be expressed as matter that is insoluble in xylene, still at O^C, and is preferably greater than or equal to 60%. Preferably the polybutene-1 used in the carriers of the present invention has a melting point of crystalline form 2 (the first to form, being favored kinetically) from 81 to 109°C. Suitable polymers of butene-1 are both the photopolymers and the copolymers preferably containing up to 30 mol.% of olefin co monomers (in particular ethylene and alpha-olefins containing from 5 to 8 carbon atoms). These polymers can be obtained, for example, by low-pressure Ziegler-Mata polymerization of butene-1, for example by polymerizing butene-1 (and any co monomers) with catalysts based on Tec, or homogenates compounds of titanium supported on magnesium chloride, and suitable co-catalysts (in particular alkyl compounds of aluminums). High values of melt flow rate are obtained by successive treatment of the polymer with peroxides. The polymers of butene-1 used in the carriers of the present invention are solid polymers at room temperature. The PB0800 polybutene-1 (sold by Basel) is particularly suitable for use in the concentrates of the present invention. This is a photopolymers having a melt flow rate of 200 g/10minatl90T/2.16kg. The typical physical properties of this polymer are presented in the following table: The propylene polymers that can be used in the concentrates of the present invention can be is tactic crystalline photopolymers or copolymers of propylene, without distinction. Among the copolymers, the is tactic crystalline copolymers of propylene with ethylene and/or CH2=CHR alpha-olefins in which R is an alkyl radical with 2-8 carbon atoms (for example butene-1, hexene-1, octene-1), containing more than 85 wt.% of propylene, are particularly suitable. The isotacticity index of the aforesaid polymers of propylene is preferably greater than or equal to 90, measured as the fraction that is insoluble in boiling heptanes or in xylene at room temperature (approx. 25°C). The terms "additives", "pigments" and "fillers" are commonly employed in this field for indicating the substances that are added to polymers during processing. In particular the term "pigments" includes organic and inorganic substances, such as carbon black, titanium dioxide (Toe), chromium oxides, and phthalocyanines. The term "fillers" includes substances such as talc, carbonates and micas. Both the pigments and the fillers are specific examples included within the general definition of additives. Apart from pigments and fillers, the term "additives" also generally includes the categories of substances listed below. 1) Stabilizers. Examples of stabilizers are: A) antacids, for example separates, carbonates and synthetic hydrosulfites; B) light stabilizers, for example UV absorbers, such as benzophenones, benzotriazoles, carbon black; "quenchers", generally selected from the organic complexes of nickel; HALS (Hindered Amine Light Stabilizers); C) antioxidants, for example phenols, phosphates, phosphonites and compounds that are synergistic with respect to the antioxidants, for example trimesters and theaters. 2) Process coadjutants and modifiers. Examples of the aforesaid additives are: D) nucleating agents, for example dibenzylidenesorbitol, organic carboxylic acids and their salts, such as acidic acid, benzoic acid, sodium benzoate and adipose; E) slip agents, for example educative, polyamide; F) ant blocking agents, for example silicon dioxide (Siam), synthetic zealot’s; G) lubricants and antistatic agents, for example glycerylmonostearate, waxes and paraffin oils, ethoxylated amines; H) modifiers of molecular weight and archeological properties, for example peroxides. In particular, the concentrates of the present invention prove especially suitable for the dispersion of solid substances in polyolefins. Therefore concentrates in which the additives are solid at room temperature are preened. The additives are preferably present in the concentrates of the present invention in amounts from 5 to 60 wt.%, more preferably from 5 to 50 wt.%, and especially from 20 to 40 wt.%, relative to the total weight of the concentrate. Concentrates are thus obtained containing (percentages by weight): A) from 40% to 95%, preferably from 50% to 95%, in particular from 60% to 80% of a composition comprising, relative to the total weight of A): 1) from 10% to 35%, preferably from 25% to 35%, more preferably from 30% to 35% of polybutene-1; 2) from 90% to 65%, preferably from 75% to 65%, more preferably from 70% to 65% of polypropylene; B) from 5% to 60%, preferably food 5% to 50%, in particular from 20% to 40% of one or more additives. The aforesaid percentages of A) and B) refer of course to the total weight of the concentrate. The concentrates of the present invention can be prepared by mixing the aforesaid components, employing processes and equipment that are well known in the field of processing of olefin polymers. In particular, there are essentially two processes that are most used for the processing of polyolefin-based master batches: 1) dry blend; 2) extrusion. 1) The dry blend process, consisting essentially of dry mixing, after grinding if required, of the components in the blend, envisages the use of equipment such as: a) mills (with cutters or with disks, with cryogenic plant or at room temperature); b) screens; c) mixers (continuous or turbo mixers). 2) The extrusion process consists of fluid-phase homogenization of the components of the blend. This process may or may not envisage a dry blend stage prior to the extrusion stage proper, depending on whether subsequent processing is as powders or granules, respectively. The various stages and equipment of the process are as follows: a) dry blend if required; b) feed (using gravimetric or volumetric dispensers); c) extrusion (using single-screw or twin-screw extruders; the latter can be co-rotating of the slow or fast type, or counter-rotating); d) cooling (in water, or on cooled belts); e) granulation (by a cutting unit, or with cutting in the extruder head); f) homogenization (in homogenizing silos) and packing. The concentrates of the present invention can be blended advantageously with crystalline photopolymers and copolymers of propylene. In particular, preferred examples of olefin polymers with which the concentrates of the present invention can be blended are: - crystalline photopolymers of propylene, in particular is tactic photopolymers, having an isotacticity index preferably above 93%; - crystalline polymers of propylene with ethylene and/or C4-C10 alpha-olefins, in which the total content of co monomers (for example 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene) is between 0.05 and 20 wt.% relative to the weight of the copolymer; - polymers and copolymers of ethylene, such as LDPE, HDPE, LLDPE; - electrometric copolymers of ethylene with propylene and/or C4-C10 alpha-olefins, possibly containing reduced quantities of a dynes (preferably from 1 to 10 wt.%), such as 1,4-hexadiene, 1,5-hexadiene and ethylidene-1-norbomene; - electrometric thermoplastic compositions comprising a crystalline photopolymer or copolymer of propylene as described above, and an electrometric portion containing an electrometric copolymer of ethylene as described above, typically prepared according to known methods, by mixing the components in the molten state or by sequential polymerization, and generally containing the aforesaid electrometric portion in quantities food 5 to 80 wt.%; - photopolymers and copolymers of butene-1 as described previously in connection with the carrier of the concentrates of the present invention, possibly blended with the electrometric thermoplastic compositions described above. In this way a polyolefin composition is obtained containing the additives originally present in the concentrate, and ready for the processing required for obtaining the finished (manufactured) products. The methods of blending can be the same as described previously for blending the components of the concentrates of the present invention. The invention will now be described in detail with reference to a specific, non-limiting example and referring to the appended diagram (Fig. 1) which is a graph of the variation of the dispersion index of the pigment in the polymer bulk with increasing proportion of polybutene-1 in the binary mixture. The invention will be described in detail with reference to a test that evaluates the dispersion of the pigment in the carrier whenever the final master batch (carrier with added pigment) is then to be used for coloring polypropylene during its conversion to fiber. In fact, as noted earlier among the methods of processing of polypropylene, that relating to its conversion to fibers has proved to be the most critical with respect to the colorings stage and therefore this test involves spinning of the polypropylene included in the master batch. The binary mixture was prepared using a polybutene-1 having a melt flow rate (MFR) equal to 200 g/10 min (measured at 189T/2.16 kg) and a melting point (MP) of 124-nS'^C. The polybutene-1 was added in amounts between 0 and 35% to a homopolymeric polypropylene with MFR of 25 g/10 min (measured according to ASTM D 1238 L) and a content refractions soluble in xylene at room temperature of 3.5 wt.%, and the binary mixture obtained each time constituted 80% of the master batch, the rest being pigment. The pigment used is CINQUASIA Red B RT-79O-D5 a pigment in the class of quinacridone colorants and known to be very difficult to disaggregate and disperse. The dispersion and disposability of the pigment in the binary mixture obtained were then evaluated with the so-called "Filter test". This is based on monitoring the variation in pressure produced by the fluid mass on a fisher located downstream from the extrusion head during the polymer spinning process. In particular, the increase in pressure, relative to a neutral resin taken as reference, produced by the master batch or better still by the undeserved pigment that is deposited on the filter, is measured. In practice, the pressure is measured near the filter before and after passage of the master batch through the extrusion-spinning equipment, during passage of the neutral reference resin through the same. Using this test, it is possible to evaluate the carrier by calculating the following index: I = (Primal - Ponytail) / g where Pontiac represents the pressure measured at the end of passage of the neutral reference resin, but before introduction of the master batch, Fay represents the pressure after passage of the master batch, measured during the next passage of the neutral reference resin, g represents the grams of pigment filtered and I is the index of dispersion, in which: Index I Index 0.25 Index 0.35 Index I > 0.5 product not recommended for fibers. Various master batches were prepared with varying amounts of polybutene-1 in the carrier: respectively 0,10,15,20,25,25,35% based on the total quantity of carrier. The stages and the measurements that will now be described were therefore effected six times, corresponding to the various master batches containing carriers with increasing amounts of polybutene-1 (as stated in the preceding paragraph), and the value of I was calculated each time. Thus, a hopper was charged with 700 g of master batch (carrier plus pigment) previously extruded and in granules and containing 140 g of pigment. Then a supporting resin was added, consisting of the same resin used as neutral reference, until 1 kg of material was obtained, i.e. in an amount of 300 g. This resin has the function of diluting the master batch, which otherwise, especially for other concentrations of pigment in the master batch itself, would produce an excessive loading on the filter. The polymeric composition thus obtained was extruded in an extruder at 45 rpm applying a temperature in the various extrusion zones of 240°C, 270°C, 280°C. Then the resin discharged downstream from the extruder was made to pass through a 20 |im filter. The neutral reference resin consisted in this case of low-density polyethylene (LDPE) having a melt flow rate of 2 g/10 min measured according to ASTM 1238 condition E. The results shown in the following table were obtained: It is clear from the results that the master batch containing 100% polypropylene in the carrier is not suitable for colorings fibred: the pigment does not disperse in the carrier and clogs the filter, causing a considerable increase in pressure. The introduction of even a small percentage of polybutene-1 in the carrier (15%) produces a considerable reduction in pressure on the filter, leading to a product that can be regarded as being of good quality. The variation of the dispersion index I is shown in the accompanying diagram (Fig. 1). This graph clearly shows how increasing the percentage of polybutene-1 in the carrier improves the dispersion of the pigment in the master batch, until - for percentages of 25-35% - a product is reached that can be regarded as excellent for the coloring of polymeric fibred. On the basis of the course of the curve-shown in the appended diagram, above 35% we can expect a dispersion index that tends towards an almost constant value, which does not justify unceasing the amount of polybutene-1 in the carrier mixture. Therefore a preferred form of the present invention envisages the use of a percentage of polybutene-1 in the carrier equal to 25-35%, preferably equal to 30%, in the spinning of polypropylene. Without wishing to be linked to a theory, it is assumed that this surprising result is due on the one hand to the rheological characteristics of polybutene-1, the high fluidity of which favors the dispersion of the pigment in the carrier, and on the other hand to its influence on the process of crystallization of polypropylene (with which polybutene-1 displays perfect theological and crystalline miscibility), which leads to an increase in the . amorphous fraction and therefore of sites for insertion of pigment, which is thus better incorporated in the fluid mass. Therefore the use of this binary mixture permits excellent dispersion and disposability of the pigment. Furthermore, in view of the characteristic of creep resistance of polybutene-1 in a binary mixture, this material is preferred over other polyolefins with similar viscosity, but which might lead to breakages during the process of stretching of the fibred. The example given above is for evaluating a master batch intended for bulk coloring of polypropylene, during spieling of the latter, but the concentrates of the present invention can of course be used advantageously for the addition of additives to other polyolefins in the course of processing operations that are known to a person skilled in the art. CLAIMS 1. A concentrate comprising: a) polybutene-1; b) polypropylene; c) Up to 60% by weight of one or more additives. A concentrate according to claim 1 comprising (percentages by weight): A) From 40% to 95%, preferably from 50% to 95%, in particular from 60% to 80% of a composition comprising, relative to the total weight of A); 1) From 10% to 35%, preferably from 25% to 35%, more preferably from 30% to 35% of polybutene-1; 2) From 90% to 65%, preferably from 75% to 65%, more preferably from 70% to 65% of polypropylene; B) From 5% to 60%, preferably from 5% to 50%, in particular from 20% to 40% of one or more additives. A concentrate according to claim 1 wherein the polybutene-1 is a linear, Semi crystalline and highly biostatic photopolymers. A concentrate according to claim 1 wherein the polypropylene is isotactic polypropylene, having an index of isotacticity greater than or equal to 90. Use of the concentrate as in the preceding claims for the dispersion of additives in polyolefins. Polyolefin articles prepared by blending polyolefins with the concentrate according to the preceding claims, followed by processing. Colored polypropylene fibred prepared by blending polyolefins with the concentrate According to the preceding claims, followed by spinning. A polyolefin composition for the preparation of concentrates of additives, Comprising (percentages by weight): a) From more than 10% to 35% of poIybutene-1, preferably from 25% to 35%, more preferably from 30% to 35%; b) From less than 90% to 65% of polypropylene, preferably from 75% to 65%, more preferably from 70% to 65%.

Documents:

423-CHENP-2006 ABSTRACT.pdf

423-CHENP-2006 CLAIMS.pdf

423-CHENP-2006 CORRESPONDENCE OTHERS.pdf

423-CHENP-2006 CORRESPONDENCE PO.pdf

423-CHENP-2006 DESCRIPTION (COMPLETE).pdf

423-CHENP-2006 FORM 1.pdf

423-CHENP-2006 FORM 18.pdf

423-CHENP-2006 FORM 3.pdf

423-CHENP-2006 PETITIONS.pdf

423-CHENP-2006 POWER OF ATTORNEY.pdf

423-chenp-2006-abstract.pdf

423-chenp-2006-claims.pdf

423-chenp-2006-correspondnece-others.pdf

423-chenp-2006-correspondnece-po.pdf

423-chenp-2006-description(complete).pdf

423-chenp-2006-drawings.pdf

423-chenp-2006-form 1.pdf

423-chenp-2006-form 3.pdf

423-chenp-2006-form 5.pdf

423-chenp-2006-pct.pdf