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ADDITIVE COMPOSITION, METHOD OF BLENDING SAME AND A LOW HAZE POLYOLEFIN MATERIAL AND PREPARATION THEREOF

20170240721 · 2017-08-24

    Inventors

    Cpc classification

    International classification

    Abstract

    The present invention relates to an additive composition and a low haze polyolefin material which may be prepared using said additive composition. In particular, the polyolefin material is prepared from a polyolefin resin composition comprising bis-3,4-dimethylbenzylidene sorbitol and bis-p-ethylbenzylidene sorbitol at a certain weight ratio. In an aspect, the present invention relates to a method for forming a polyolefin material; said method comprising: (i) preparing a polyolefin resin composition comprising polyolefin resin and bis-3,4-dimethylbenzylidene sorbitol and bis-p-ethylbenzylidene sorbitol, wherein the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the polyolefin resin composition is 45:55 to 25:75; (ii) processing said polyolefin resin composition to form said polyolefin material.

    Claims

    1. A method for forming a polyolefin material; said method comprising: (i) preparing a polyolefin resin composition comprising polyolefin resin and bis-3,4-dimethylbenzylidene sorbitol and bis-p-ethylbenzylidene sorbitol, wherein the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the polyolefin resin composition is 45:55 to 25:75; (ii) processing said polyolefin resin composition to form said polyolefin material.

    2. A method for reducing haze in a polyolefin material, wherein the polyolefin material is prepared by processing a polyolefin resin composition to form the polyolefin material; wherein said method comprises combining a polyolefin resin with bis-3,4-dimethylbenzylidene sorbitol and bis-p-ethylbenzylidene sorbitol to form said polyolefin resin composition such that the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the polyolefin resin composition is 45:55 to 25:75 prior to processing of the polyolefin resin composition into the polyolefin material.

    3. A method according to claim 1 or claim 2, wherein processing of the polyolefin resin composition to form said polyolefin material is conducted at a temperature of from 180° C. to 245° C., preferably from 185° C. to 230° C.

    4. A method for forming a polyolefin material; said method comprising: (i) preparing a polyolefin resin composition comprising polyolefin resin and bis-3,4-dimethylbenzylidene sorbitol and bis-p-ethylbenzylidene sorbitol, wherein the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the polyolefin resin composition is 45:55 to 15:85; (ii) processing said polyolefin resin composition to form said polyolefin material; and wherein processing of the polyolefin resin composition to form said polyolefin material is conducted at a temperature of no more than 200° C.

    5. A method according to any of claims 1 to 4, wherein processing of the polyolefin resin composition to form said polyolefin material is conducted at a temperature of from 180° C. to 200° C., preferably from 185° C. to 198° C., even more preferably at a temperature of from 190° C. to 197° C., most preferably from 190° C. to 195° C.

    6. A method according to any of the preceding claims wherein processing of the polyolefin resin composition comprises injection and/or extrusion moulding the polyolefin resin composition.

    7. A method according to any of the preceding claims wherein the polyolefin resin composition is melt compounded and extruded before being processed to form said polyolefin material.

    8. A method according to any of the preceding claims, wherein the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the polyolefin resin composition is 40:60 to 25:75.

    9. A method according to any of the preceding claims, wherein the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the polyolefin resin composition is 35:65 to 25:75.

    10. A method according to any of the preceding claims, wherein the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the polyolefin resin composition is 32:68 to 28:72, for example 30:70.

    11. A method according any of the preceding claims, wherein the combined amount of bis-3,4-dimethylbenzylidene sorbitol and bis-p-ethylbenzylidene sorbitol in the polyolefin resin composition is from 1000 ppm to 5000 ppm, by weight of the polyolefin resin composition.

    12. A method according to any of the preceding claims, wherein the combined amount of bis-3,4-dimethylbenzylidene sorbitol and bis-p-ethylbenzylidene sorbitol in the polyolefin resin composition is from 1500 ppm to 4000 ppm, by weight of the polyolefin resin composition; preferably 2250 ppm to 3250 ppm, by weight of the polyolefin resin composition; more preferably from 2500 ppm to 3000 ppm, by weight of the polyolefin resin composition.

    13. A method according to claim 11 or claim 12, wherein the combined amount of bis-3,4-dimethylbenzylidene sorbitol and bis-p-ethylbenzylidene sorbitol in the polyolefin resin composition is from 1500 ppm to 2500 ppm, by weight of the polyolefin resin composition; preferably from 1750 ppm to 2250 ppm, by weight of the polyolefin resin composition; more preferably from 1900 ppm to 2100 ppm, by weight of the polyolefin resin composition.

    14. A method according to any of the preceding claims, wherein the polyolefin of the polyolefin resin is selected from the group consisting of polypropylene, polyethylene, polybutylene, or blends or copolymers thereof.

    15. A method according to claim 14, wherein the polyolefin is polypropylene or copolymer thereof.

    16. A method according to any of the preceding claims, wherein the polyolefin resin has a melt flow rate of 5 g/10 min or above, as measured according to ASTM method D1238-04.

    17. A method according to any of the preceding claims, wherein the polyolefin resin has a melt flow rate of 20 g/10 min or above, as measured according to ASTM method D1238-04.

    18. A method according to any of the preceding claims wherein the melt flow rate of the polyolefin resin is 40 g/10 min or above as measured according to ASTM method D1238-04.

    19. A method according to any of the preceding claims wherein the melt flow rate of the polyolefin resin is 70 g/10 min or above as measured according to ASTM method D1238-04.

    20. A method according to any of the preceding claims, wherein the polyolefin material has a haze value, as measured in accordance with ASTM D1003-61 for a 1 mm thick plaque, of below 20%, more preferably below 15%, still more preferably below 13%, most preferably below 12%.

    21. A nucleating and clarifying additive composition comprising or consisting essentially of bis-3,4-dimethylbenzylidene sorbitol and bis-p-ethylbenzylidene sorbitol, wherein the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the additive composition is 45:55 to 25:75.

    22. A nucleating and clarifying additive composition according to claim 21, wherein the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the additive composition is 40:60 to 25:75.

    23. A nucleating and clarifying additive composition according to claim 21 or claim 22, wherein the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the additive composition is 35:65 to 25:75.

    24. A nucleating and clarifying additive composition according to any of claims 21 to 23, wherein the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the additive composition is 32:68 to 28:72, for example 30:70.

    25. A polyolefin resin composition as defined in any of claims 1, 2 or any of the preceding claims when dependent thereon.

    26. A polyolefin material comprising: (a) polyolefin; (b) bis-3,4-dimethylbenzylidene sorbitol; and (c) bis-p-ethylbenzylidene sorbitol; wherein the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the polyolefin material is from 45:55 to 25:75.

    27. A polyolefin material according to claim 26, wherein the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the polyolefin material is 40:60 to 25:75.

    28. A polyolefin material according to claim 26 or claim 27, wherein the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the polyolefin material is 35:65 to 25:75.

    29. A polyolefin material according to any of claims 26 to 28, wherein the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol in the polyolefin material is 32:68 to 28:72, for example 30:70.

    30. A polyolefin material according to any of claims 26 to 29, wherein the polyolefin is selected from the group consisting of polypropylene, polyethylene, polybutylene, or blends or copolymers thereof.

    31. A polyolefin material according to claim 30, wherein the polyolefin is polypropylene or a copolymer thereof.

    32. A polyolefin material according to any of claims 26 to 31, wherein the polyolefin material has a haze value, as measured in accordance with ASTM D1003-61 for a 1 mm thick plaque, of below 20%, more preferably below 15%, still more preferably below 13%, most preferably below 12%.

    33. A polyolefin material prepared by the method of any of claims 1 to 20.

    34. A polyolefin material prepared from a polyolefin resin having a melt flow rate of least 40 g/10 min, as measured in accordance with ASTM method D1238-04, which when moulded at 180° C. has a haze value of less than 20%, as measured in accordance with ASTM D1003-61, for a plaque of 1 mm thickness.

    35. A polyolefin material according to claim 34, wherein the polyolefin resin has a melt flow rate of less than 500 g/10 min, as measured in accordance with ASTM method D1238-04, preferably less than 200 g/10 min, more preferably less than 150 g/10 min.

    36. A polyolefin material according to claim 34 or claim 35, wherein moulding at 180° C. comprises injection moulding.

    37. Use of a combination of bis-3,4-dimethylbenzylidene sorbitol and bis-p-ethylbenzylidene sorbitol in a bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol weight ratio of 45:55 to 25:75 in the preparation of a nucleated and/or clarified polyolefin material, for broadening the processing temperature over which a nucleated and/or clarified polyolefin material may be prepared in comparison with the preparation of a nucleated and/or clarified polyolefin material using bis-3,4-dimethylbenzylidene sorbitol or bis-p-ethylbenzylidene sorbitol as the sole clarifying and/or nucleating agent; wherein the haze value of the nucleated and/or clarified polyolefin material is less than 20%, measured in accordance with ASTM D1003-61 for a plaque of 1 mm thickness.

    38. Use according to claim 37 wherein processing of the polyolefin resin composition comprises injection and/or extrusion moulding said polyolefin resin composition.

    39. Use according to claim 37 or 38 wherein the total concentration of processing bis-3,4-dimethylbenzylidene sorbitol and bis-p-ethylbenzylidene sorbitol clarifying and nucleating agents used in a polyolefin resin composition as part of the preparation of the polyolefin material is as defined in any of claims 11 to 13.

    40. Use of bis-3,4-dimethylbenzylidene sorbitol for lowering the solubility point of bis-p-ethylbenzylidene sorbitol in a molten resin.

    41. Use of bis-p-ethylbenzylidene sorbitol for lowering the solubility point of bis-3,4-dimethylbenzylidene sorbitol in a molten resin.

    42. Use of a combination of bis-3,4-dimethylbenzylidene sorbitol and bis-p-ethylbenzylidene sorbitol in the preparation of a nucleated and/or clarified polyolefin material at processing temperatures of 200° C. or below.

    43. Use of a combination of bis-3,4-dimethylbenzylidene sorbitol and bis-p-ethylbenzylidene sorbitol in the preparation of a nucleated and/or clarified polyolefin material having a haze value of less than 20%, measured in accordance with ASTM D1003-61 for a plaque of 1 mm thickness, at processing temperatures of 200° C. or below.

    Description

    [0068] The present invention will now be illustrated by way of the following examples and with reference to the following figures:

    [0069] FIG. 1: Graphical representation for solubility point (° C.) determination from the maximum value for relative brightness variability for different concentrations of 3,4-DMDBS in a molten propylene random copolymer resin (MFR 7 g/10 min);

    [0070] FIG. 2: Graphical representation of the solubility point (° C.) for different concentrations of 3,4-DMDBS, EDBS and blends thereof in a molten propylene random copolymer resin (MFR 7 g/10 min);

    [0071] FIG. 3: Graphical representation of solubility point (° C.) for various blends of 3,4-DMDBS and EDBS in molten propylene random copolymer resin (MFR 7 g/10 min), at a combined concentration of 3000 ppm, based on the total weight of the resin composition, as well as haze values for a polyolefin material prepared by injection moulding the corresponding resin composition at 180° C. (“IM-180° C.”);

    [0072] FIG. 4: Graphical representation of solubility point (° C.) for various blends of 3,4-DMDBS and EDBS in molten propylene random copolymer resin (MFR 7 g/10 min), at a combined concentration of 3000 ppm, based on the total weight of the resin composition, as well as haze values for a polyolefin material prepared by injection moulding the corresponding resin composition at 190° C. (“IM-190° C.”);

    [0073] FIG. 5: Graphical representation of solubility point (° C.) for various blends of 3,4-DMDBS and EDBS in molten propylene random copolymer resin (MFR 7 g/10 min), at a combined concentration of 2500 ppm, based on the total weight of the resin composition, as well as haze values for a polyolefin material prepared by injection moulding the corresponding resin composition at 180° C. (“IM-180° C.”);

    [0074] FIG. 6: Graphical representation of solubility point (° C.) for various blends of 3,4-DMDBS and EDBS in molten propylene random copolymer resin (MFR 7 g/10 min), at a combined concentration of 2500 ppm, based on the total weight of the resin composition, as well as haze values for a polyolefin material prepared by injection moulding the corresponding resin composition at 190° C. (“IM-190° C.”);

    [0075] FIG. 7: Graphical representation of solubility point (° C.) for various blends of 3,4-DMDBS and EDBS in molten propylene random copolymer resin (MFR 80 g/10 min), at a combined concentration of 2500 ppm, based on the total weight of the resin composition, as well as haze values for a polyolefin material prepared by injection moulding the corresponding resin composition at 180° C. (“IM-180° C.”);

    [0076] FIG. 8: Graphical representation of solubility point (° C.) for various blends of 3,4-DMDBS and EDBS in molten propylene random copolymer resin (MFR 50 g/10 min), at a combined concentration of 2500 ppm, based on the total weight of the resin composition, as well as haze values for a polyolefin material prepared by injection moulding the corresponding resin composition at 180° C. (“IM-180° C.”);

    [0077] FIG. 9: Graphical representation of solubility point (° C.) for various blends of 3,4-DMDBS and EDBS which also comprise in molten propylene random copolymer resin (MFR 50 g/10 min), at a combined concentration of 3000 ppm, based on the total weight of the resin composition, as well as haze values for a polyolefin material prepared by injection moulding the corresponding resin composition at 180° C. (“IM-180° C.”); and

    [0078] FIG. 10: Graphical representation of melting points for 3,4-DMDBS, EDBS and blends thereof.

    EXAMPLES

    Solubility Point

    [0079] The solubility point (° C.) was measured using compounded pelletized samples of base resin (described in further detail below). The particular compounded pellets were melt compounded at 190° C., thereby avoiding complete dissolution of the clarifier/nucleating agent. The clarifier/nucleating agent containing pellets were melted above the polyolefin's softening point (>160° C.) at a rate of 10° C./min up to 230° C. As the temperature increased, the underlying clarifier/nucleating agent dispersion eventually melted completely into the molten resin and the temperature was recorded following completion of the phase change. Molten pellets were observed using a microscope (BX41, Olympus) with hot stage (FP90, Mettler). Changes in light transmittance values were obtained and recorded in a plot of “relative brightness variability” vs. “temperature”, the solubility point of the clarifier being defined as the temperature at which the maximum relative brightness variability value is observed in this plot; the lower the measured temperature, the higher the solubility of clarifier in the molten resin.

    [0080] FIG. 1 corresponds to the plot observed when determining the solubility point of different concentrations (1000, 2000, 3000 and 4000 ppm) of 3,4-DMDBS in molten polypropylene “RACO” MFR 7 g/10 min. Maximum values for relative brightness variability and corresponding temperature (solubility point) are shown to increase as the concentration of 3,4-DMDBS in the molten resin composition is increased. FIG. 1 illustrates, by virtue of the changing relative brightness variability, that significant dissolution of the clarifier/nucleating agent in the resin composition is observed at temperatures below the measured solubility point.

    Haze Value

    [0081] The haze value of the polyolefin material formed was measured according to ASTM Standard Test Method D1003-61 “Standard Test Method for Haze and Luminous Transmittance of Transparent Plastics” using a Gardner Hazegard Plus.

    General Procedure for Preparation of Polyolefin Material

    [0082] The base resin (random copolymer, hereinafter “RACO”) and all additives were weighed and then blended in a Super mixer for 2 minutes at 1500 rpm. All samples were then melt compounded on a twin screw extruder at a ramped temperature from about 170° C. to 185° C. The melt temperature upon exit of the extruder die was about 190° C. Pelletized samples were subsequently used for solubility point measurements. Plaques of the target polyolefin material were then made on 25 ton injection moulder using the pelletized samples. The moulder barrel was set at the specific temperature indicated below. Plaques were prepared having dimensions of 75 mm×75 mm×Z mm, where thickness, Z, is 0.5 mm, 1 mm or 2 mm, using a mirror-polished mould. Cooling circulating water in the mould was controlled at a temperature of 25° C. Once prepared, the plaques were rested for 24 hours at room temperature before being analysed to determine their respective Haze values.

    [0083] The polyolefin base resin used in the present examples was a polypropylene of the following composition:

    Polypropylene random copolymer powder—1000 g
    Irganox® 1010, Primary Antioxidant (from BASF)—500 ppm
    Irgafos® 168, Secondary Antioxidant (from BASF)—500 ppm

    Calcium Stearate, Acid Scavenger—500 ppm

    [0084] Clarifying compounds or compositions—(as indicated below)

    [0085] Mixtures of 3,4-DMDBS and EDBS were prepared by admixing the two components in powder form at the desired ratio, before being blended with the base resin as described above.

    [0086] 3,4-DMDBS was obtained from New Japan Chemical (Geniset® DXR). EDBS was prepared in accordance with the following method. A 5 L reaction kettle, equipped with a stirrer and nitrogen inlet, was charged with 400 g of sorbitol in 2400 g of methanol. 416 g of ethylbenzaldehyde and a catalyst methanol solution (6 g of p-toluenesulfonic acid in 100 g of methanol) were added to the reaction vessel. The solution was stirred at 50° C. for 24 hours, during which time a white precipitate formed, which was isolated by filtration and washed with methanol to give a white powder. The powder was suspended at pH 8 with a small amount of KOH, and the suspension heated to boiling point, then filtered. The white powder obtained was washed with boiling water and further neutralized to pH 7. The suspension was heated to boiling point before being filtered. The precipitated white powder obtained was rinsed with methanol before a further filtration afforded a white solid. The isolated white powder was dried in a vacuum oven at 80° C. to give 370 g of EDBS product having a purity above 99% (58% yield).

    Example 1

    [0087] The solubility points of 3,4-DMDBS and EDBS at different concentrations in molten polypropylene “RACO” MFR 7 g/10 min were determined and the results are provided below in Table 1.

    TABLE-US-00001 TABLE 1 3,4- 3,4- Solubility DMDBS EDBS DMDBS:EDBS Point (ppm) (ppm) ratio (° C.) 1000 0 100:0 199 1400 0 100:0 204 1600 0 100:0 207 1800 0 100:0 210 2000 0 100:0 212 3000 0 100:0 219 4000 0 100:0 225 0 2000   0:100 190 0 2500   0:100 194 0 3000   0:100 197 0 4000   0:100 203 750 1750  30:70 190 1000 1500  40:60 194 1250 1250  50:50 200 900 2100  30:70 191 1200 1800  40:60 196 1500 1500  50:50 202

    [0088] The results in Table 1 show that EDBS is highly soluble in molten polypropylene, even at high concentrations (e.g. 4000 ppm), having a solubility point significantly lower than that of 3,4-DMDBS at equivalent concentrations. However, EDBS alone has less favourable organoleptic properties, as described above. Furthermore, blends of 3,4-DMDBS and EDBS at a weight ratio in accordance with the invention have lower solubility points than 3,4-DMDBS and even EDBS, when used alone at the same concentration as the total blend concentration and in the same polyolefin resin.

    [0089] For example, at a concentration of 3000 ppm, the solubility point of 3,4-DMDBS in the polypropylene random copolymer resin was observed to be 219° C. and, at a concentration of 3000 ppm, the solubility point of EDBS in the same polypropylene random copolymer resin was observed to be 197° C. In contrast, a blend of 3,4-DMDBS and EDBS in a ratio according to the invention (30:70) at a combined concentration of 3000 ppm (900 ppm+2100 ppm) in the same polypropylene random copolymer resin was observed to be 191° C. Notably, a blend of 3,4-DMDBS and EDBS at a weight ratio not in accordance with the invention (50:50) at a combined concentration of 3000 ppm (1500 ppm+1500 ppm) in the same polypropylene random copolymer resin was observed to be 202° C., significantly higher than the solubility point of EDBS at a concentration of 3000 ppm in the same polypropylene random copolymer resin.

    [0090] A selection of the above results is also represented graphically in FIG. 2, from which the synergistic effects of the blend of 3,4-DMDBS and EDBS at a weight ratio according to the invention can be seen.

    Example 2

    [0091] The solubility points of 3,4-DMDBS, EDBS and blends thereof at different concentrations in molten polypropylene “RACO” MFR 7 g/10 min were determined followed by determination of haze values for polypropylene materials prepared therefrom in accordance with the general procedure described above. The results are provided in Table 2 below.

    TABLE-US-00002 TABLE 2 Haze Solu- (ASTM-D1003-61 - 3,4- 3,4- bility 1 mm) DMDBS EDBS DMDBS:EDBS Point IM- IM- IM- (ppm) (ppm) ratio (° C.) 180° C. 190° C. 200° C. 2000 0 100:0  212 28.9 17.2 10.6 0 1500  0:100 — 12.9 12.8 13.2 0 2000  0:100 190 11.6 11.8 12.4 0 2500  0:100 194 11.9 11.3 12.0 0 3000  0:100 197 11.9 11.1 11.5 250 2250 10:90 194 11.3 11.0 11.3 500 2000 20:80 194 11.1 10.9 — 750 1750 30:70 190 11.2 11.6 12.0 1000 1500 40:60 194 11.9 10.9 12.0 1250 1250 50:50 200 18.8 10.7 11.1 1500 1000 60:40 204 22.6 11.2 10.3 1750 750 70:30 207 26.9 19.6 10.8 2000 500 80:20 212 27.9 17.7 10.1 2250 250 90:10 212 30.1 20.1 9.5 300 2700 10:90 194 11.2 10.5 11.0 600 2400 20:80 194 10.3 10.4 10.5 900 2100 30:70 191 10.6 10.4 11.3 1200 1800 40:60 196 13.0 9.9 10.3 1500 1500 50:50 202 19.7 9.8 10.1 1800 1200 60:40 206 23.8 12.5 10.1 2000 1000 66:33 208 25.2 13.7 10.5 2100 900 70:30 213 26.6 18.4 9.9 2400 600 80:20 213 30.5 28.1 9.6 2700 300 90:10 219 34.3 29.6 9.5 2000 1000 66:33 208 25.2 13.7 10.5 2000 1500 57:43 208 22.2 11.6 9.5 2000 2000 50:50 209 24.0 11.7 9.4

    [0092] The results in Table 2 were used to prepare Haze Value/Solubility Point plots against 3,4-DMDBS:EDBS ratio for the total concentrations in resin (2500 ppm or 3000 ppm) and for different injection moulding temperatures (180° C. and 190° C.). These plots correspond to FIGS. 3 to 6. The results in Table 2, and FIGS. 3 to 6, demonstrate the synergistic effects in terms of solubility of the nucleating and clarifying agents and transparency of the polyolefin material prepared, which are simultaneously observed at 3,4-DMDBS:EDBS ratios according to the invention. In particular, these synergistic effects are observed at the lower than conventional injection moulding temperatures of 180° C. and 190° C. The results in Table 2 also demonstrate that suitable haze values are also obtained at higher injection moulding temperatures (200° C.), demonstrating that the invention can also be applied at conventional processing temperatures. Polyolefin materials prepared comprising 3,4-DMDBS and EDBS in a weight ratio in accordance with the present invention had good organoleptic properties. This is in contrast to polyolefin materials prepared with EDBS alone, which had a noticeable sweet odour. Meanwhile, adequate haze and organoleptic properties in nucleated and clarified polyolefin material is also shown to be possible where the weight ratio of bis-3,4-dimethylbenzylidene sorbitol to bis-p-ethylbenzylidene sorbitol used in the polyolefin resin composition is as high as 15:85 (as in the alternative aspect of the present invention), provided processing temperatures do not exceed 200° C.

    Example 3

    [0093] The solubility points of 3,4-DMDBS, EDBS and blends thereof at different concentrations in molten polypropylene “RACO” MFR 80 g/10 min were determined followed by determination of haze values for polypropylene materials prepared therefrom in accordance with the general procedure described above. The results are provided in Table 3 below.

    TABLE-US-00003 TABLE 3 Haze Solu- (ASTM-D1003-61 - 3,4- 3,4- bility 1 mm) DMDBS EDBS DMDBS:EDBS Point IM- IM- IM- (ppm) (ppm) ratio (° C.) 180° C. 190° C. 200° C. 2000 0 100:0  215 47.7 45.9 12.6 2500 0 100:0  219 48.6 45.4 28.8 3000 0 100:0  223 51.2 47.5 37.8 0 2000  0:100 — 23.1 18.9 19.0 0 2500  0:100 187 24.3 19.1 18.4 0 3000  0:100 194 28.2 18.6 18.0 600 1400 30:70 195 18.7 17.9 18.2 800 1200 40:60 200 20.5 18.0 20.5 750 1750 30:70 196 18.9 16.9 16.9 1000 1500 40:60 202 20.3 14.4 13.5 900 2100 30:70 200 20.8 13.3 13.6 1200 1800 40:60 205 23.8 13.0 12.7

    [0094] The results in Table 3 were used to prepare the Haze Value/Solubility Point plot against 3,4-DMDBS:EDBS ratio corresponding to FIG. 7 for a total concentration in resin of 2500 ppm and for an injection moulding temperature of 180° C. FIG. 7 and the results in Table 3 further demonstrate the synergistic effects described hereinbefore for ratios of 3,4-DMDBS to EDBS according to the invention with a polypropylene resin having a high MFR value (80 g/10 min). Polyolefin materials prepared comprising 3,4-DMDBS and EDBS in a weight ratio in accordance with the present invention had good organoleptic properties. This is in contrast to the polyolefin materials prepared with EDBS alone, which had a noticeable sweet odour.

    Example 4

    [0095] The solubility points of 3,4-DMDBS, EDBS and blends thereof at different concentrations in molten polypropylene “RACO” MFR 80 g/10 min were determined followed by determination of haze values for polypropylene materials prepared therefrom (0.5 mm plaque thickness) in accordance with the general procedure described above. The results are provided in Table 4 below.

    TABLE-US-00004 TABLE 4 Haze (ASTM-D1003-61 - 3,4- 3,4- Solubility 0.5 mm) DMDBS EDBS DMDBS:EDBS Point IM- IM- (ppm) (ppm) ratio (° C.) 190° C. 200° C. 2500 0 100:0  219 20.0 11.1 750 1750 30:70 195 3.7 3.5 1000 1500 40:60 202 3.8 3.8 0 2500  0:100 187 8.3 4.2

    [0096] The results in Table 4 further demonstrate the synergistic effects described hereinbefore for ratios of 3,4-DMDBS to EDBS according to the invention with a polypropylene resin having a high MFR value (80 g/10 min). Polyolefin materials prepared comprising 3,4-DMDBS and EDBS in a weight ratio in accordance with the present invention had good organoleptic properties. This is in contrast to the polyolefin material prepared with EDBS alone, which had a noticeable sweet odour.

    Example 5

    [0097] The solubility points of 3,4-DMDBS, EDBS and blends thereof at different concentrations in molten polypropylene “RACO” MFR 80 g/10 min were determined followed by determination of haze values for polypropylene materials prepared therefrom (2.00 mm plaque thickness) in accordance with the general procedure described above. The results are provided in Table 5 below.

    TABLE-US-00005 TABLE 5 Haze 3,4- 3,4- Solubility (ASTM-D1003-61 - DMDBS EDBS DMDBS:EDBS Point 2.0 mm) (ppm) (ppm) ratio (° C.) IM-190° C. 2500 0 100:0  219 77.4 750 1750 30:70 195 37.6 1000 1500 40:60 202 37.8 0 2500  0:100 187 43.9

    [0098] The results in Table 5 further demonstrate the synergistic effects described hereinbefore for ratios of 3,4-DMDBS to EDBS according to the invention with a polypropylene resin having a high MFR value (80 g/10 min). Polyolefin materials prepared comprising 3,4-DMDBS and EDBS in a weight ratio in accordance with the present invention had good organoleptic properties. This is in contrast to the polyolefin material prepared with EDBS alone, which had a noticeable sweet odour.

    Example 6

    [0099] The solubility points of 3,4-DMDBS, EDBS and blends thereof at different concentrations in molten polypropylene “RACO” MFR 50 g/10 min were determined. Polyolefin materials were subsequently prepared by injection moulding the resin composition at various temperatures and the haze values determined as described in the general procedure above. The results provided below in Table 6 below.

    TABLE-US-00006 TABLE 6 3,4- 3,4- DMDBS EDBS DMDBS:EDBS Solubility Haze (ASTM-D1003-61-1 mm) (ppm) (ppm) ratio Point (° C.) IM-180° C. IM-190° C. IM-200° C. 2000 0 100:0  212 41.3 33.6 14.8 2500 0 100:0  214 44.1 37.2 33.4 3000 0 100:0  223 44.0 41.0 36.1 0 2000  0:100 — 21.3 18.4 20.3 0 2500  0:100 186 22.4 17.6 19.2 0 3000  0:100 195 22.9 17.7 17.6 600 1400 30:70 194 15.4 15.5 17.3 800 1200 40:60 198 18.8 15.1 16.0 750 1750 30:70 195 19.2 12.6 14.8 1000 1500 40:60 201 21.0 12.0 13.0 900 2100 30:70 197 19.3 9.2 15.0 1200 1800 40:60 201 20.1 14.7 12.0

    [0100] The results in Table 6 were used to prepare Haze Value/Solubility Point plots against 3,4-DMDBS:EDBS ratio for a total concentration in resin of 2500 ppm and 3000 ppm for an injection moulding temperature of 180° C., corresponding to FIGS. 8 and 9 respectively. FIGS. 7 and 8, and the results in Table 6, further demonstrate the synergistic effects described hereinbefore for ratios of 3,4-DMDBS to EDBS according to the invention with a polypropylene resin having MFR value of 50 g/10 min. Polyolefin materials prepared comprising 3,4-DMDBS and EDBS in a weight ratio in accordance with the present invention had good organoleptic properties. This is in contrast to the polyolefin materials prepared with EDBS alone, which had a noticeable sweet odour.

    Example 7

    [0101] The solubility points of 3,4-DMDBS, EDBS and blends thereof at different concentrations in molten polypropylene “RACO” MFR 48 g/10 min were determined. Polyolefin materials were subsequently prepared by injection moulding the resin composition at various temperatures and the haze values determined as described in the general procedure above. The results are provided below in Table 7 below.

    TABLE-US-00007 TABLE 7 Haze Solu- (ASTM-D1003-61 - 3,4- 3,4- bility 1 mm) DMDBS EDBS DMDBS:EDBS Point IM- IM- IM- (ppm) (ppm) ratio (° C.) 180° C. 190° C. 200° C. 2000 0 100:0  211 43.3 39.9 13.4 2500 0 100:0  213 43 41.5 16.3 3000 0 100:0  — 46.7 45.2 — 0 2000  0:100 — 19.0 19.1 19.3 0 2500  0:100 184 21.1 18.1 19.0 0 3000  0:100 193 25.4 17.6 17.7 600 1400 30:70 193 17.2 17.9 17.5 800 1200 40:60 195 17.0 16.6 16.4 750 1750 30:70 195 17.5 14.8 14.7 1000 1500 40:60 198 22.3 14.3 14.0 900 2100 30:70 199 16.1 13.8 13.7 1200 1800 40:60 202 22.0 13.1 12.1

    [0102] The results in Table 7 further demonstrate the synergistic effects described hereinbefore for ratios of 3,4-DMDBS to EDBS according to the invention with a polypropylene resin having MFR value of 48 g/10 min. Polyolefin materials prepared comprising 3,4-DMDBS and EDBS in a weight ratio in accordance with the present invention had good organoleptic properties. This is in contrast to the polyolefin materials prepared with EDBS alone, which had a noticeable sweet odour.

    Example 8

    [0103] The solubility points of 3,4-DMDBS, EDBS and blends thereof at a concentration of 2000 ppm in molten polypropylene “RACO” MFR 40 g/10 min were determined. Polyolefin materials were subsequently prepared by injection moulding the resin composition at various temperatures and the haze values determined as described in the general procedure above. The results are provided below in Table 8 below.

    TABLE-US-00008 TABLE 8 Haze Solu- (ASTM-D1003-61 - 3,4- 3,4- bility 1 mm) DMDBS EDBS DMDBS:EDBS Point IM- IM- IM- (ppm) (ppm) ratio (° C.) 180° C. 190° C. 200° C. 0 2000  0:100 193 25.6 18.4 18.8 2000 0 100:0  207 47.4 36 25.1 200 1800 10:90 192 19.4 17.3 17.9 400 1600 20:80 191 17.7 15.4 16.0 500 1500 25:75 191 14.9 14.9 15.4 600 1400 30:70 190 15.4 14.7 15.3 800 1200 40:60 190 17.0 15.0 15.2 1000 1000 50:50 191 21.9 15.3 15.4 1200 800 60:40 198 29.1 18.2 14.9 1400 600 70:30 203 38.9 20.6 14.4 1600 400 80:20 204 43.2 31 13.2 1800 200 90:10 206 48.4 29.8 17.2

    [0104] The results in Table 8 further demonstrate the synergistic effects described hereinbefore for ratios of 3,4-DMDBS to EDBS according to the invention with a polypropylene resin having MFR value of 40 g/10 min. Polyolefin materials prepared comprising 3,4-DMDBS and EDBS in a weight ratio in accordance with the present invention had good organoleptic properties. This is in contrast to the polyolefin materials prepared with EDBS alone, which had a noticeable sweet odour.

    Example 9

    [0105] The haze values were determined for a series of polyolefin materials prepared from blends of 3,4-DMDBS and EDBS at a concentration of 2000 ppm in molten polypropylene “RACO” MFR 40 g/10 min. One set of polyolefin materials was prepared by melt compounding the blend of 3,4-DMDBS and EDBS and RACO and extruding at 190° C. before injection moulding the resin composition at various temperatures. Another set of polyolefin materials was prepared by mixing the blend of 3,4-DMDBS and EDBS and powdered RACO before injection moulding at various temperatures. The results are provided below in Table 9a and Table 9b below.

    TABLE-US-00009 TABLE 9a preparation including extrusion Haze (ASTM-D1003-61 - 3,4- 3,4- 1 mm) DMDBS EDBS DMDBS:EDBS IM- IM- IM- (ppm) (ppm) ratio 180° C. 190° C. 200° C. 0 2000  0:100 25.6 18.4 18.8 400 1600 20:80 19.7 15.4 16.0 500 1500 25:75 14.9 14.9 15.4 600 1400 30:70 15.4 14.7 15.3 800 1200 40:60 17.0 15.0 15.2 2000 0 100:0  21.9 15.3 15.4

    TABLE-US-00010 TABLE 9b preparation without extrusion Haze (ASTM-D1003-61 - 1 mm) 3,4- 3,4- IM- IM- IM- IM- DMDBS EDBS DMDBS:EDBS 170° 180° 190° 200° (ppm) (ppm) ratio C. C. C. C. 0 2000  0:100 38.8 26.9 20.2 20.7 400 1600 20:80 35.6 22.1 16.4 17.4 500 1500 25:75 32.5 15.8 16.3 16.9 600 1400 30:70 23.5 16.0 16.3 16.3 800 1200 40:60 27.4 19.7 16.3 16.4 2000 0 100:0  54.9 54.4 39.0 13.5

    [0106] A comparison of the haze values of Tables 9a and 9b illustrates the additional advantage of including a melt compounding and extrusion step prior to moulding of the resin composition in the preparation of the polyolefin material. In particular, a reduction in haze values is exhibited by melt compounding and extruding the resin composition prior to moulding to prepare the polyolefin material in comparison to just mixing the components of the resin composition and moulding only. Thus, in order to enhance the effects of the present invention, the polyolefin material may be prepared by melt compounding and extruding the resin composition prior to injection moulding to form the polyolefin material.

    Example 10

    [0107] The melting point of various blends of 3,4-DMDBS and EDBS were determined to assess the effect of the relative proportions of the components on the melting point of the blend. Results are provided in Table 10 below together with the solubility points for the majority of blends in molten polypropylene “RACO” MFR 40 g/10 min at a concentration of 2000 ppm. Then trend of melting points for the various blends is also represented graphically in FIG. 10.

    TABLE-US-00011 TABLE 10 3,4- 3,4- Solubility DMDBS EDBS DMDBS:EDBS m.p. Point (ppm) (ppm) ratio (° C.) (° C.) 0 2000  0:100 244.9 193 500 1500 25:75 244.0 — 600 1400 30:70 241.8 190 800 1200 40:60 241.9 190 1000 1000 50:50 243.7 191 1100 900 55:45 249.1 — 1200 800 60:40 251.2 198 1500 500 25:75 257.5 — 2000 0 100:0  275.3 207

    [0108] The results in Table 10 (as well as FIG. 10) illustrate that the melting point of the blend does not merely reflect the respective melting points of the two components of the blend and their relative proportions in each of the blends. Surprisingly, the results indicate that the blends form a eutectic system having a eutectic point, where the melting point of the blend is lowest and lower than the respective melting points of the individual components alone, for a 3,4-DMDBS to EDBS ratio of approximately 30:70. It will also be appreciated that this eutectic blend of 3,4-DMDBS and EDBS also coincides with the blend of 3,4-DMDBS and EDBS exhibiting one of the lowest solubility points in the molten resin.

    [0109] The surprising eutectic system exhibited by the blend of 3,4-DMDBS and EDBS is considered to further illustrate the effects of the invention. Without being bound by any particular theory, it is believed that the correlation observed between the melting point of the blends and the solubility point of the blend in molten resin indicates that the eutectic properties of the blend contribute to the ability of the resin composition to be processed at lower than conventional temperatures to form a clarified and/or nucleated polyolefin material having excellent haze properties.