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USOO8445567B2

(12) United States Patent (10) Patent No.: US 8.445,567 B2 Stevenson et al. (45) Date of Patent: May 21, 2013

(54) METHOD FOR REDUCING PLATE-OUT OF (56) References Cited SOLID PHOSPHITES IN POLYMERS U.S. PATENT DOCUMENTS (75) Inventors: Donald Stevenson, Dover, OH (US); 2004/0164279 A1* 8, 2004 Stevenson et al...... 252/.397 Michael Jakupca, Canton, OH (US); 2006/0173109 A1* 8/2006 Keegan et al...... 524f109 Nina Bersaglini, Magnolia, OH (US) OTHER PUBLICATIONS (73) Assignee: Dover Chemical Corporation, Dover, Spatafore et al., “Migration and Blooming of Stabilizing OH (US) Antioxidants in Polypropylene' Polym. Engineering and Science, Nov. 1991, vol. 31, No. 22, pp. 1610-1617.* (*) Notice: Subject to any disclaimer, the term of this PCT/US2010/24911 International Preliminary Report on Patentabil patent is extended or adjusted under 35 ity form PCT/IB/373, dated Aug. 23, 2011. U.S.C. 154(b) by 411 days. PCT/US2010/24911 International Search Report form PCT/ISA/ 210. (21) Appl. No.: 12/709,883 PCT/US2010/24911 International Written Opinion Form PCT/ISA/ 237 dated Apr. 12, 2010. Filed: Feb. 22, 2010 Spatafore, et al. Migration and Blooming of Stabilizing Antioxidants (22) in Polypropylene Polymer Engineering and Science, Aug. 26, 2004, (65) Prior Publication Data vol. 31, Issue 22, pp. 1610-1617. US 2010/0216923 A1 Aug. 26, 2010 * cited by examiner Primary Examiner — Robert D. Harlan Related U.S. Application Data (74) Attorney, Agent, or Firm — Hahn Loeser & Parks LLP (60) Provisional application No. 61/154,531, filed on Feb. 23, 2009. (57) ABSTRACT A process is described which reduces the amount of bloom (51) Int. C. and/or plate-out of phosphite antioxidants during polymer CSK 3/52 (2006.01) processing by the addition of at least one (52) U.S. C. (or blends thereof) or polycaprolactones (or blends thereof) USPC ...... 524/128: 524/140; 524/141 having an average molecular weight of approximately 1,000 (58) Field of Classification Search to 20,000, most preferably between 4,000 to 10,000. USPC ...... 524/128, 141, 140 See application file for complete search history. 14 Claims, No Drawings US 8,445,567 B2 1. 2 METHOD FOR REDUCING PLATE-OUT OF SUMMARY OF THE INVENTION SOLID PHOSPHITES IN POLYMERS The invention herein described includes the use of a TECHNICAL FIELD defined molecular weight range of polyalkylene glycols, including polyethylene glycols, polypropylene glycols and The invention described herein pertains generally to a polycaprolactones which when used above a minimum con method to prevent the “migration” or “plate-out” or “bloom' centration, can reduce and prevent the migration and/or plate of high performance or general purpose solid phosphites from out of solid diphosphites and monophosphites Such as Dover polyolefins, including preferably polyethylenes, especially phos(R) S-9228TM (bis(2,4-dicumylphenyl) linear low density polyethylenes and low density polyethyl 10 diphosphite) or Doverphos(R) S-480 (tris(2,4-di-t-butylphe enes, and polypropylene during processing and aging. More nyl)phosphite) in polyolefins, e.g., low density polyethylene, specifically the invention relates to a process to reduce the linear low density polyethylene and polypropylene during migration or plate-out of high performance Solid diphosphites processing and aging. such as Doverphos(R) S-9228TM (bis(2,4-dicumylphenyl)pen 15 In one embodiment, the molecular weight range of poly taerythritol diphosphite) and solid monophosphites such as (PEG) is from about 1,000 to 20,000, more Doverphos(R) S-480 (tris(2,4-di-t-butylphenyl) phosphite) preferably from about 2,000 to about 15,000, most preferably when blended into polyolefins. The invention is expected to from about 4,000 to about 10,000, and in one preferred have applicability to other phosphites, although to different embodiment, is approximately 8000. PEG is added at a con degrees, a non-limiting list including distearyl pentaerythritol centration which is effective compared to a composition with diphosphite (Doverphos(RS-680), bis-(2,4-di-t-butylphenyl) no added PEG. In another embodiment polypropylene glycol, pentaerythritol diphosphite (UltranoxR 626), bis-(2,6-di-t- the molecular weight range of (PPG) is from 400 to 8000 and butyl-4-methylphenyl)pentaerythritol diphosphite (PEP 36), more preferably 3000 to 4000. The PPG is added at a con and 2.2.2"-nitrilo triethyl-tris3.3',5,5'-tetra-tert-butyl-1,1'- centration which is effective compared to a composition with biphenyl-2,2'-diylphosphite (Irgafos(R 12). 25 no PPG. In another embodiment, polycaprolactones (PCL) with molecular weight range of 400 to 15,000 are added, and BACKGROUND OF THE INVENTION more preferably with a molecular weight range from 2,000 to 8000. The PCL is added at a concentration which is effective Solid phosphites, particular high performance Solid phos compared to a composition with no PCL. phites, are very good stabilizers for the processing of linear 30 low density polyethylene (“LLDPE), high density polyeth In one embodiment, the PEG, PPG, and PCL are added in ylene (“HDPE), low density polyethylene (“LDPE) and an amount which is within approximately 150% of an amount polypropylene (“PP). One particular high performance solid of said diphosphite, alternatively within approximately 100% phosphite, namely Doverphos(R S-9228TM (bis(2,4-di of the diphosphite, and in yet another alternative, within cumylphenyl)pentaerythritol diphosphite) has proven to be a 35 approximately 50% of said amount of diphosphite. In some very good polymer stabilizer. (See U.S. Pat. Nos. 5,364,895: applications, the added amounts will be essentially equal. 5,438,086; 7,176,252: 6,613,823; 6,224,791; 6,770,693; and Secondary additives may also be added, these additives 6,680,351.) Although Doverphos(R S-9228TM gives excellent selected from the group consisting of magnesium oxide, Zinc color and melt flow stability during processing of LLDPE and oxide, calcium Stearate, magnesium Stearate, and hydrotal LDPE, when used at moderate to high levels (over 250 ppm) 40 cite. it will plate-out on the processing equipment or plate-out on In another embodiment of the invention, blends of PEG, the plastic part after aging, both of which are undesirable. PPG and PCL, particularly are employed. The problem with plating-out on process equipment is that These and other objects of this invention will be evident the there is a build up of residual phosphite on some of the when viewed in light of the detailed description and appended processing parts thereby requiring that the process be stopped 45 claims. and the equipment cleaned. In the case of extruded LLDPE film or blown LLDPE film, the Doverphos(R) S-9228TM plates DETAILED DESCRIPTION OF THE INVENTION out on the rolls resulting in particles of S-9228TM being trans ferred to the film. Additionally, not only does the S-9228TM The best mode for carrying out the invention will now be plate out on the processing equipment, but on aging some of 50 described for the purposes of illustrating the best mode the S-9228TM migrates to the surface of the polyethylene known to the applicant at the time. The examples are illustra (“PE) film. In the case of PE stretch film the S-9228TM tive only and not meant to limit the invention, as measured by appears as a powder on the Surface and prevents the stretch the scope and spirit of the claims. As used in this application, film from adhering to itself. “plate-out” is the migration of additives to manufacturing At least one prior art solution described in WO 2006/ 55 083.642 A1, disclosed a method of reducing the plate-out by equipment during processing while “bloom' is the migration the incorporation of a dibenzylidene, with a clarifying agent of additives to the Surface of the polymer after aging. during polypropylene processing by including the use of one Doverphos(R) S-9228TM is a high performance diphosphite or more co-additives. The co-additives used were selected that gives good melt flow stability and good color stability from the group consisting of homopolymers of ethylene 60 during polymer processing. Tables 1-3 give some of the per oxide, copolymers containing ethylene oxide segments, pro formance data of S-9228TM compared to the general purpose pylene oxide and polycaprolactone and derivatives and com solid monophosphite, Doverphos(R) S-480. Both formulas binations. contained 400 ppm of Dovernox-10 (tetrakis methylene (3.5- Thus, there is a great need to find away or process to be able di-t-butyl-4-hydroxyhydrocinnamate) methane) and 400 to use solid diphosphites and monophosphites at higher levels 65 ppm of CaSt (calcium stearate). S-9228T is bis(2,4-di in LLDPE and LDPE without the attendant problem of plate cumylphenyl)pentaerythritol diphosphite with less than 5% out and/or bloom. triisopropanolamine added by weight. US 8,445,567 B2 3 4 As used in this application, the phosphite additive weights, i.e. they are polydisperse. The size distribution can S-9228TM (bis(2,4-dicumylphenyl)pentaerythritol diphos be characterized Statistically by its weight average molecular phite) is the following phosphite additive commercially avail weight (M) and its number average molecular weight (M), able from Dover Chemical Corporation. the ratio of which is called the polydispersity index (M/M). CH3 O O CH3-(O) CH -CH3 H3C CH

As used in this application, the phosphite additive S-480. The performance of the diphosphite S-9228TM was com also known as Irgafos(R 168, (tris(2,4-di-t-butylphenyl) phos pared and contrasted to the monophosphite S-480 in LLDPE, phite) is the following phosphite additive commercially avail HDPE and PP as illustrated in Tables 1-3. able from Dover Chemical Corporation and others, e.g., Ciba Corporation. TABLE 1

25 Performance of S-9228 ' Compared to S-480 in LLDPE YI Color Stability MFI Stability (230 C. (230 C. Additive 1. Pass 3 Pass 5 Pass 1 Pass 3 Pass 5 Pass

30 S-9228 TM -1.6 -2.9 -1.9 21.8 21.8 20.3 (600 ppm) S-48O O.2 3.1 S.O 22.6 22.2 20.8 Also, as used in this application, poly(ethylene glycol) (1200 ppm) (“PEG'), and polypropylene glycol (PPG) also known as poly(ethylene oxide) (“PEO) or poly() 35 (“PPO') respectively, are polyethers and refers to an oligomer TABLE 2 or polymer of ethylene oxide or propylene oxide and are typically liquids or low-melting Solids, depending on their Performance of S-9228 "Compared to S-480 in HDPE molecular weight. PEGs and PPGs are typically prepared by YI Color Stability MFI Stability the polymerization of ethylene oxide or propylene oxide and 40 230° C. 230° C. are commercially available over a wide range of molecular Additive 1. Pass 3 Pass 5' Pass 1' Pass 3 Pass 5' Pass weights from 300 g/mol to 10,000,000 g/mol. Differentforms S-9228T 2.0 4.2 S.6 27.9 29.9 30.2 of PEG or PPG are also available dependent on the initiator (500 ppm) used for the polymerization process. The most common of S-48O 3.2 5.4 6.2 28.3 29.8 30.3 which is a monofunctional methyl PEG (methoxypoly 45 (1000 ppm) (ethylene glycol)) or methyoxypolypropylene glycol, abbre viated mPEG and mPPG. PEGs and PPG are also available with different geometries. Branched polymers have 3 to 10 polyglycol chains emanating from a central core group. Star TABLE 3 50 polymers have 10-100 polyglycol chains emanating from a Performance of S-9228 M Compared to S-480 in PP central core group. Comb PEGs and PPGs have multiple polyglycol chains normally grafted to a polymer backbone. YI Color Stability MFI Stability PEG and PPG melting points vary depending on the For (260 C. (260° C. Additive 1. Pass 3 Pass 5 Pass 1 Pass 3 Pass 5 Pass mula Weight of the polymer. PEG or PEO has the following 55 chemical structure: S-9228 TM 4.3 7.9 8.3 16.0 21.0 27.0 (400 ppm) S-48O 6.0 8.5 1O.O 17.0 24.0 3O.O (800 ppm) while PPG has the following chemical structure 60 As seen from the above experimental results, in general S-9228TM can be used at approximately one half the concen The numbers that are often included in the names of PEGs tration levels of S-480 and still give excellent results. In low or PPGs indicate their average molecular weights, e.g. a PEG density polyethylene, like LLDPE, a high level of S-480 with n=9 would have an average molecular weight of approxi 65 (about 800 to 1500 ppm) must be used to give stability for five mately 400 Daltons and would be labeled PEG 400. Most passes in an extruder. The performance of phosphites is deter PEGs include molecules with a distribution of molecular mined by running multi-pass extrusions, collecting the poly US 8,445,567 B2 5 6 mer after each pass. The color and melt flow index is then TABLE 6 measured after the first, third and fifth pass through the extruder. The less change in color and melt flow, the better the Phosphite Migration Results in Over at 70° C. (LLDPE performance of the phosphite. Typically a primary antioxi 3 Days 5 Days dant is also used at levels of 200 to 1500 ppm in these multi pass extrusion tests. Formula Thin film 20 mil Thin film 20 mil S-480 by itself, when used at levels required to give good performance, gives plate-out. Even S-9228TM, which offers equivalent to Superior performance at lower concentrations of 10 5 the additive, exhibited plate-out. S-9228TM was added at 450 ppm in a LLDPE cast film application. On aging for one month, it was found that S-9228TM was blooming onto the Surface of the LLDPE film. The bloom of S-9228TM affects The data indicates that even down to a level of 350 ppm, the clarity of the film. It also negatively impacts film adhesion 15 S-9228TM after 5 days shows some evidence of migration or if it is a stretch film. Even S-9228TM added at levels as low as bloom from the LLDPE. 300 ppm in LLDPE exhibited bloom. It is interesting to note Another study was conducted on the degree of migration that the blooming and plate-out problems do not occur in (bloom) as a function of S-9228TM concentration in LLDPE HDPE. Many co-additives were tried with S-9228TM to see if and as a function of temperature, the results of which are it was possible to eliminate the migration or bloom. These shown in Table 7. Additives were weighed separately from the included various esters and plasticizers and several polyeth resin LLDPE (which contained 711 ppm of S-480). LLDPE ylene glycols. was added to a Brabender Bowl Mixer attemperature of 225° C. Once resin was fused, the additives were added. The com The procedure for evaluating plate-out or blooming which pound was mixed for about 2 minutes. The compound was was employed was as follows. The phosphite additive e.g., 25 removed from the bowl and compression molded into films S-9228TM by itselfor with co-additives into LLDPE (obtained and plaques (20 mil) for compatibility testing at the following from Nova Chemicals Corporation or other LLDPE supplier) temperatures: 70° C., 50° C. and room temperature. In the was blended using a Brabender bowl mixer at 220° C. and 45 tables, the following rating was employed: 0 No Bloom; rpm for five minutes. The polymer containing the additives 1- Very Slight Bloom; 2 Slight Bloom; 3—Moderate was removed from the bowl and compression molded into 20 30 Bloom; and 4 Heavy Bloom. mil thick films at 180°C. for 5 minutes. The film was then cut into 4x4 inch squares and suspended in a 50° C. or 70° C. oven TABLE 7 for several days. Each day the films were checked for bloom on the Surface. Table 4 gives a list of Some of phosphites at Bloom as a function of amount of added S-9228 TM various levels. Table 5 gives the performance of these phos 35 Additive Days Exposed at 70 C. phites as a stabilizer and Table 6 gives results with regard to bloom. S-480 (ppm) S-9228 TM (ppm) 1 5 7 14 21 7 O O 1 O O TABLE 4 7 2OO O 1 1 1 2 40 7 250 O 1 1 2 2 7 3OO O 1 2 2 2 Additive (ppm) D E F 7 350 O 1 2 2 2 7 450 O 1 3 3 76 O O 1 1 1 S-9228T 6SO 550 450 350 325 Days Exposed at 50° C. 45 S-48O 325 1OOO 7 O O O O O DN10 200 2OO 200 2OO 200 2OO 7 2OO O O O 1 1 7 250 O O O 1 1 7 3OO O O 1 1 1 7 350 O 1 1 1 2 7 450 O 1 1 1 2 50 TABLE 5 76 O O O O 1 Days Exposed at R.T. A. B C D E F 7 O O O O O 7 2OO O O O O O Melt Flow (g/10 min) 7 250 O O O O O 55 7 3OO O O O O O 1 Pass 4.27 4.40 4.28 4.27 4.31 4.24 7 350 O O O O O 3 Pass 3.92 3.99 3.75 3.52 3.82 3.60 7 450 O O O O 1 76 O O O O O 4. Pass 3.SO 3.59 3.31 3.01 3.38 3.14 5 Pass 2.90 3.07 2.69 2.43 NA NA Color (YI) 60 The results show that even the addition of S-9228TM at 200 ppm S-9228TM, some migration (bloom) will occur after 21 1 Pass -3.0 -2.8 -2.7 -1.7 -2.2 -1.9 days at 70° C. Minimal migration (bloom) occurs with the 3 Pass -0.5 O 1.O O.1 O.2 -0.1 control. 4. Pass O.1 0.7 1.2 O.8 1.6 0.7 A further study was performed to evaluate several additives 5 Pass 0.4 1.5 1.7 1.7 2.2 1.3 65 to determine if a reduction could be achieved for the migra tion of S-9228TM in LLDPE. The following procedure was employed: Additives were weighed separate from the resin US 8,445,567 B2 7 8 followed by adding the resin to the Brabender Bowl Mixer TABLE 10 when temperatures reached 225°C. Once the resin had fused, the additives were added and the materials were mixed for 2 Days minutes. The compound was removed from the bowl and Compound LLDPE 1 3 4 8 14 16 22 compression molded into thin films for analytical testing and 5 Base 1 2 2 2 2 2 2 20 mill plaques for compatibility testing. Each formulation Base' + 100 ppm 2 3 3 3 4 4 4 was compounded 4 times in order to produce enough material PEG 8000 for compression molding plaques. Base' + 200 ppm 1 1 2 2 2 3 3 PEG 8000 As shown in Table 8, it has been discovered that higher 10 Base' + 300 ppm 1 1 2 2 2 2 2 molecular weight PEG gives the best results in preventing PEG 8000 Base' + 400 ppm 1 1 1 1 1 1 1 bloom. Several different molecular weight PEGs were evalu PEG 8000 ated including 400, 600, 1000, 1500 and 8000. Of the poly Base' + 500 ppm 1 1 1 1 1 1 1 ethylene glycols tested, PEG 8000 gave the best results. Many PEG 8000 tests were then carried out to optimize the level of the PEG 15 8000 and the amount of S-9228TM that could be made com 0-no bloom; 1-very slight bloom; 2-slight bloom; 3-moderate bloom; and 4-heavy bloom. patible in the LLDPE resin. The data shows that for S-9228TM added at 450 ppm to the polymer, a 400 to 500 ppm level of PEG 8000 is needed to TABLE 8 stop migration. 2O The addition of the PEG 8000 does result in a slightly Material (ppm darker color compared to no added PEG. The PEG 8000 does A. B C D E F G not seem to affect the melt flow stability. Table 11 below shows these results in which the Control was LLDPE con LLDPE 45 g 45 g 45 g 45 g 45 g 45 g 45 g S-9228T 750 750 750 750 750 750 750 taining 300 ppm S-480& 450 ppm S-9228TM. DN10 500 500 500 500 500 500 500 25 Additive TABLE 11 PEG 400 500 YI Color Stability MFI Stability PEG 600 500 PEG 1 OOO 500 (220 C. (220 C. PEG, Stearate 500 30 Additive 1. Pass 3 Pass 5 Pass 1 Pass 3 Pass 5 Pass PEG 1500 500 PEG 8000 500 Control -1.5 -1.0 -0.3 2.8 2.6 2.0 Control + -1.0 O.2 1.O 2.8 2.6 2.2 PEGStearate = monostearate ester of PEG 600 500 ppm PEG 8000 Plaques having a thickness of 20 mils were pressed out 35 from each of the formulations compounded in Table 8 and the It was found that the addition of MgO could improve the results summarized in Table 9. A plaque for each formulation color when used with the PEG 8000 as illustrated in the was suspended in a 70° C. oven and checked every couple of compositions made in accordance with Table 12. The formu days for blooming using a rating scale of 0 to 3 with 0 being 40 lations of Table 12 were compounded in a Brabender bowl no bloom and 3 being complete bloom. mixer for 15 minutes at 200° C. plaques were pressed and used to measure color using the YI index. TABLE 9 TABLE 12 Results of Bloom Study - 70° C. Migration of S-9228 TM to Film Surface 45 Additive (ppm Rating (O - no bloom to 3 A. B C D E Formula Additive Results complete bloom) LLDPE 45 g 45 g 45 g 45 g 45 g A None Migration 7 days (2) 14 days (3) S-9228 TM 450 450 450 450 B PEG 400 Complete exudation 50 PEG 8000 500 500 500 C PEG 600 Complete exudation MgO 250 D PEG 1 OOO Complete exudation MgSt 250 E PEG/Stearate Complete exudation YI 24 15 29 16 17 F PEG 1500 Complete exudation G. PEG 8000 Minor migration 4 days (1), 7 days (1), 14 days (2.5) 55 Making sure that MgO would not affect the migration of the S-9228TM in LLDPE, more tests were performed in which another set of material was compounded in the Brabender The optimum level of PEG 8000 to use with S-9228TM, to Bowl Mixer to be able to test compatibility. Two new PEGs prevent migration, was determined by running some experi with lower molecular weights were evaluated in the formula ments where a relatively high level of S-9228TM (450 ppm) in 60 tion to determine if they help to reduce the bloom of S-9228T. LLDPE was tested with various levels of the PEG 8000. The One formulation also contained magnesium oxide. This was LLDPE resinused contained 450 ppm S-9228TM and 300 ppm used to determine if it would help to reduce the added color of the S-480 (Base formulation). The various compounds the PEGs give to the formulations. The following formula were prepared as described previously using a Brabender tions were compounded as shown in Table 13. bowl mixer, the resulting compounds were pressed into 20 65 The formulations were compounded using LLDPE at 160° mil plaques and then aged in a 70° C. oven. The results are C. and 45 RPM for 2 minutes. The material was then collected summarized in Table 10. from the bowl and compression molded into plaques. These US 8,445,567 B2 9 10 plaques were placed into a 70° C. oven to observe for com All of the material that was compounded was removed patibility. The following results were recorded in Table 13. from the bowl mixer and compression molded into 20 mil thick films. These films were cut into 4x4 inch plaques and TABLE 13 placed in a 50° C. oven to observe for compatibility. The 5 samples were looked at periodically over a couple of weeks to Additive (ppm determine if the PEG 8000 helps to reduce or eliminate the A. B C D exudation. After 16 days (a) 50° C. it was decided to increase the LLDPE 45 g 45 g 45 g 45 g temperature to 70° C. to force exudation. Compatibility was S-9228T 450 450 450 450 10 S-48O 3OO 300 3OO 300 observed periodically with the following observations as PEG 8000 500 500 illustrated in Table 15. MgO 250 PEG 1 OOO 500 TABLE 1.5 PEG 1450 500 Bloom (days (a) 70° C.) 15 Additive (ppm 1 O O 1 1 A. B C D E F 2 O O 1 1 6 O O 1 1 LLDPE 45 g 45 g 45 g 45 g 45 g 45 g 9 O O 1 1 S-48O 600 8SO 1100 1100 1100 1100 12 O O 1 PEG 8000 550 700 1OOO Bloom (days at 50° C.) The data in Table 13 shows that MgO at 250 ppm did not 1 O O O O O O affect migration also shows that some lower Molecular 3 O O O O O O Weight polyethylene glycols were not as effective as the 6 O O O.S O O O 8 O.S O.S O.S O O O higher molecular weight polyethylene glycols, e.g., see PEG 25 13 O.S O.S O.S O O O 8OOO. 16 O.S O.S O.S O O O Other additives were evaluated to see if they could improve Bloom (after 16 days at 50° C. and 4 days at 70° C.) the color of LLDPE, S-9228TM and the PEG 8000. These other additives included CaSt (calcium stearate), ZnO (Zinc 2O 1 1 1 O O O oxide) DHT4A (hydrotalcite) and MgSt (magnesium stear ate) as shown in Table 14. The above formulations were 30 The use of PEG 8000 stops or at least minimizes the plate mixed in Brabender Bowl Mixerfor 20 minutes at 225°C. and out (bloom) of S-480 in LLDPE. compression molded plaques were prepared on each and then Polypropylene glycol and polycaprolactones were also colorYI measured. The results show again that MgO gives the evaluated to see if they could prevent the blooming of S9228 best improvement in color. in polymers especially in LLDPE. In this evaluation we used TABLE 1.4 Additive (ppm A. B C D E F

LLDPE 45 g 45 g 45 g 45 g 45 g 45 g 45 9. 45 g S-9228 TM 450 450 450 450 450 4SO 450 PEG 8000 500 500 500 500 500 500 MgO 250 CaSt 250 ZnO 250 DHT4A 250 MgSt 250 YI 9.1 8.9 14.2 9.4 12.0 15.8 14.2 11.6 (after mixing 20 minutes (a)225° C.)

While S-9228TM can used at relatively low levels in an improved method for determining migration to the Surface. LLDPE, it is recognized that S-480 needs to be used at very The initial gloss of plaques was read and then the gloss was high levels, typically over 1000 ppm in LLDPE in order to read after aging in oven over time. If migration occurs, the give good MFI and color. S-480 will bloom at these high 55 gloss goes down drastically if there is not migration the gloss levels. It has been discovered that the addition of PEG 8000 remains the same or decreases very little. Table 16 shows the will improve (i.e., reduce) the bloom and plate-out problem of results of the evaluation of several PCLs, and PPG. S-480. All formulations were compounded in the Brabender Bowl A series of experiments were performed to evaluate the 60 Mixer at 160° C. for 2 minutes after the additives were added compatibility of S-480 in NOVA Chemicals Corporation to the bowl mixer. Plaques were pressed and placed into a 70° LLDPE resin with PEG 8000 to determine if polyethylene C. oven. Gloss was measured as a way to track compatibility. glycol would work in the same manner as with S-9228TM and A change in gloss measurement indicates that there is exuda to determine at what level the S-480 will exude out of the tion on the Surface of the plaque. The greater the change in LLDPE. The material was compounded in a bowl mixer at 65 gloss the greater the amount of exudate present. Where there 220° C. and 45 RPM for 5 minutes each. The following is not a value for gloss, it indicates that a significant change in formulations were used and summarized in Table 15. gloss occurred (excessive exudation) from the previous US 8,445,567 B2 11 12 inspection and testing was ceased for that particular formu TABLE 17-continued lations. Each formulation was also tested for yellowness index. Gloss measurements were performed using a BYK Migration test using gloss measurements after aging. Gardner micro-gloss 60° meter per ASTM D 2457. Agloss meter is used to measure gloss on plaques that have Additive Gloss been placed in the oven. Each plaque is placed onto brown Amount-Type Day 0 Day 114 felt. A calibration is run each time the gloss meteris turned on. 7SO - 28O3PCL8000 O.9 -2.0 Three measurements are taken at three different locations on 800 - PEG8OOO 4.1 -1.6 each plaque. The gloss meter records each of these measure 1000 - PEG8OOO -1.1 -5.4 ments are reports the average of these measurements. These 10 measurements are tracked over time and change in gloss is observed. These formulations were processed with EXXON LLDPE resin, all formulation contain 650 ppm of S9228T ((bis(2,4- TABLE 16 dicumylphenyl)pentaerythritol diphosphite)+triisopropanol 15 amine). Migration test using gloss measurements after aging As used hereinabove, processed with NOVA LLDPE resin PCL 2043 400 is Perstorp CAPA 2043, a low 400, MW Gloss: lineardiol, MP 0 to -10°C., viscosity at 60°C.-40 poise: PCL 2047A 400A is Perstorp 2047A, a low 400 MW Composition Day Day Day Day premium grade, 0 to -10°C. mp, viscosity at 60°C.-40 (ppm-compound ppm-compound) O 8 18 132 poise; No Additive 90.6 84.3 83.9 82.6 PCL 2403 D4000 is Perstorp 2403D premium grade linear 6SO-S9228T 90.2 777 6SO-S9228TSOO-PPG3SOO 93.3 90 90.1 90.4 diol from capolactone, MW 4000, 55 to 60° C. mp, 650-S9228T 750-PPG3500 87.9 86.6 86.9 85.3 viscosity 1670 poise at 60° C.; 6SO-S9228TSOO-PCL1 OOOO 86.3 85.8 84.3 83.9 25 PCL 2803 8000 is Perstorp 2803, linear, 8000 MW, MP 55 6SO-S9228T,7SO-PCL1 OOOO 87.8 88.7 87 88 6SO-S9228TSOO-PCL2OOO 86.6 85.5 83.5 8O.S to 60° C. and viscosity at 60° C. of 8600 poise: 6SO-S9228T,7SO-PCL2OOO 82.8 80.2 84.7 76.1 PCL 10000 from Aldrich, 10,000 MW, mp 60° C.; 6SO-S9228TSOO-PCL-THF 93.9 89.8 90.3 87.9 PCL 2000-DIOL from Aldrich, 2000 MW mp36 to 48° C.: 6SO-S9228T,7SO-PCL-THF 92.3 89.8 90.3 88.3 PCL-THF- from Aldrich, a polycaprolactone-block-poly Color:YIYellowness index 30 tetrahydrofuran-block polycaprolactone mp30-33°C.; No Additive 3.2 2 -0.6 and 6SO-S9228T 1.3 1.3 PPG 3500 from Aldrich, poly() MW 6SO-S9228TSOO-PPG3SOO 5.4 2.8 10.3 650-S9228T 750-PPG3500 3.1 2.4 2.2 3500, viscous liquid at 25°C.-13000 poise at 25°C. 6SO-S9228TSOO-PCL1 OOOO 4.6 3.6 -0.2 35 Therefore, what has been shown is that S-9228TM is a high 6SO-S9228T,7SO-PCL1 OOOO 2.6 2.8 2.3 performance phosphite giving excellent performance in sta 6SO-S9228TSOO-PCL2OOO-DIOL 4.9 4.2 -0.4 6SO-S9228T,7SO-PCL2OOO-DIOL O -0.9 O.9 bilizing LLDPE during processing. But, at the levels required 6SO-S9228TSOO-PCL-THF 1.4 -0.4 8.O to give good stabilization (greater than 250 ppm), S-9228TM 6SO-S9228T,7SO-PCL-THF O.3 -1.0 O.S will bloom onto the surface of the polymer. In this discovery, 40 it has been found that by using PEG 8000, or PPG 3500 or Table 17 give the results using an EXXON LLDPE com PCL 2000 to 10000 as a co-additive at a level of at least 500 paring some polycaprolactones to the PEG8000. PEG 8000 ppm, the blooming of solid phosphites such as S-9228TM, S-480, S-680, Ultranox(R 626, PEP36 or Irgafos(R) 12, can be was used since it gave the best results for the PEGs. minimized, if not prevented. 45 The invention has been described with reference to pre TABLE 17 ferred and alternate embodiments. Obviously, modifications Migration test using gloss measurements after aging. and alterations will occur to others upon the reading and understanding of the specification. It is intended to include all Additive Gloss Such modifications and alterations insofar as they come Amount-Type Day 0 Day 114 50 within the scope of the appended claims or the equivalents thereof. SOO - 2043PCL400 813 65.6 7SO - 2043PCL400 76.7 692 SOO - 2047APCL4OOA 76 66.2 What is claimed is: 7SO - 3047APCL4OOA 73 61.4 1. A process to reduce bloom or plate-out of solid phosphi SOO - 24O3DPCL4OOO 76.6 79.3 55 tes in polyolefins comprising the step of: 7SO - 24O3DPCL4OOO 84.5 84.9 SOO - 28O3PCL8000 79.6 81.4 adding an amount of a co-additive selected from the group 7SO - 28O3PCL8000 78.8 80.2 consisting of polyalkylene glycol, polycaprolactone and 800 - PEG8OOO 87.6 84.2 blends thereof, to said polyolefin, 1000 - PEG8OOO 88.2 86.2 Color, YI yellowness Index said amount of said co-additive being no less than 50% 60 of said solid phosphite, and SOO - 2043PCL400 8 3.6 a molecular weight of said co-additive being Sufficient to 7SO - 2043PCL400 1.4 -3.5 reduce said bloom or plate-out of said solid phosphi SOO - 2047APCL4OOA 1.9 -3.6 7SO - 2047APCL4OOA 1 -3.7 tes in comparison to when no co-additive is added. SOO - 24O3DPCL4OOO 1.9 -2.0 2. The process of claim 1 wherein 7SO - 24O3DPCL4OOO 6.2 1.7 65 said polyalkylene glycol is polyethylene glycol, and SOO - 28O3PCL8000 2.6 -1.5 said molecular weight of said polyethylene glycol ranges from about 1,000 to 20,000. US 8,445,567 B2 13 14 3. The process of claim 2 wherein said polyolefin is selected from the group consisting of said polyalkylene glycol is polyethylene glycol, and linear low density polyethylene, low density polyethyl said molecular weight of said polyethylene glycol ranges ene, medium density polyethylene and polypropylene, and from about 2,000 to 15,000. said solid phosphite is bis(2,4-dicumylphenyl)pentaeryth 4. The process of claim 3 wherein ritol diphosphite, said phosphite added in an amount of said polyalkylene glycol is polyethylene glycol, and at least about 500 ppm. said molecular weight of said polyethylene glycol ranges 13. The process of claim 1 wherein from about 4,000 to 10,000. said co-additive is polyethyethylene glycol having a 5. The process of claim 1 wherein molecular weight of at least approximately 8000, said said polyalkylene glycol is polypropylene glycol, and 10 polyethylene glycoladded in an amount of at least about said molecular weight of said polypropylene glycol ranges 400 ppm, and from about 400 to 8,000. said polyolefin is selected from the group consisting of linear low density polyethylene, low density polyethyl 6. The process of claim 5 wherein ene, medium density polyethylene and polypropylene, said polyalkylene glycol is polypropylene glycol, and 15 and said molecular weight of said polypropylene glycol ranges said solid phosphite is tris (2,4-di-t-butylphenyl)phosphite, from about 3,000 to 4,000. said phosphite added in an amount of at least about 300 7. The process of claim 1 wherein ppm. said co-additive is polycaprolactone and said molecular 14. The process of claim 1 wherein weight of said polycaprolactone ranges from about 400 said co-additive is selected from the group consisting of to 15,000. polyethyethylene glycol having a molecular weight of at 8. The process of claim 7 wherein least approximately 8000, said polyethylene glycol said co-additive is polycaprolactone and said molecular added in an amount of at least about 250 ppm, weight of said polycaprolactone ranges from about polypropylene glycol having a molecular weight of at 2,000 to 8,000. 25 least approximately 3500, said polypropylene glycol 9. The process of claim 1 wherein added in an amount of at least about 250 ppm, said Solid phosphite is selected from the group consisting polycaprolactone having a molecular weight of at least of (bis(2,4-dicumylphenyl)pentaerythritol diphosphite), approximately 2000, said polycaprolactone added in (tris (2,4-di-t-butylphenyl)phosphite), distearyl pen an amount of at least about 250 ppm, and taerythritol diphosphite, bis-(2,4-di-t-butylphenyl)pen 30 blends of polyethylene glycol, polypropylene glycol, taerythritol diphosphite, bis-(2,6-di-t-butyl-4-meth polycaprolactone, ylphenyl)pentaerythritol diphosphite, and 2,2'2"-nitrilo said polyolefin is selected from the group consisting of triethyl-tris(3,3',5,5'-tetra-tert-butyl-1,1'-biphenyl-2, linear low density polyethylene, low density polyethyl 2'-diylphosphite. ene, medium density polyethylene and polypropylene, 10. The process of claim 2 wherein 35 and said amount of said co-additive being no less than 100% of said solid phosphite is selected from the group consisting said solid phosphite. of (bis(2,4-dicumylphenyl)pentaerythritol diphosphite), 11. The process of claim 10 wherein (tris (2,4-di-t-butylphenyl)phosphite), distearyl pen said amount of said co-additive being no less than 150% of taerythritol diphosphite, bis-(2,4-di-t-butylphenyl)pen said solid phosphite. 40 taerythritol diphosphite, bis-(2,6-di-t-butyl-4-meth 12. The process of claim 1 wherein ylphenyl)pentaerythritol diphosphite, and 2,2'2"-nitrilo said co-additive is polyethyethylene glycol having a triethyl-tris(3,3',5,5'-tetra-tert-butyl-1,1'-biphenyl-2, molecular weight of at least approximately 8000, said 2'-diylphosphite, said phosphite added in an amount of polyethylene glycoladded in an amount of at least about at least about 500 ppm. 400 ppm, and ck ck sk k ck