WO2022079613A1

WO2022079613A1 - Polylactone-based synergists with fluorinated polymer processing additives

Info

Publication number: WO2022079613A1
Application number: PCT/IB2021/059371
Authority: WO
Inventors: Chetan P. Jariwala; Claude LAVALLÉE
Original assignee: 3M Innovative Properties Company
Priority date: 2020-10-14
Filing date: 2021-10-12
Publication date: 2022-04-21

Abstract

Synergists comprising at least one polylactone block and a comonomer block are described. Such synergists may be used in combination with a fluorinated polymer processing additive to reduce melt fracture when processing thermoplastic materials by, for example, extrusion casting or melt blowing the composition. Both diblock and triblock polylactone-based synergists are described. Suitable comonomer blocks include poly(alkylene ether) and polydialkylsiloxane. Suitable thermoplastic polymers include polyolefins such as linear low-density polyethylene.

Description

POLYLACTONE-BASED SYNERGISTS WITH FLUORINATED POLYMER PROCESSING ADDITIVES

FIELD

[0001] The present disclosure relates to polylactone-based synergists that, in combination with a fluorinated polymer processing additive, may be used to reduce melt fracture when processing thermoplastic materials.

SUMMARY

[0002] Briefly, in one aspect, the present disclosure provides compositions comprising a thermoplastic polymer, a fluorinated polymer processing additive and a synergist. The synergist is a block copolymer comprising at least one polylactone block and a comonomer block. Suitable comonomer blocks include poly(alkylene ether) and polydialkylsiloxane. The weight ratio of the synergist to fluorinated polymer processing additive may be from 4:6 to 9: 1, inclusive. Suitable thermoplastic polymers include polyolefins such as linear low-density polyethylene.

[0003] In another aspect, the present disclosure provides methods of reducing melt fracture comprising forming the compositions of the present invention and extruding the compositions. In some embodiments, the compositions are melt-blown to form films.

[0004] The details of one or more embodiments of the invention are also set forth in the description below. Other features, objects, and advantages of the invention will be apparent from the description and from the claims.

DETAILED DESCRIPTION

[0005] Extrusion of polymeric materials in the formation and shaping of articles is a major segment of the plastic or polymeric articles industry. The quality of the extruded article and the overall success of the extrusion process are influenced by the interaction of the fluid material with the extrusion die. The desire for a smooth extrudate surface competes with, and must be optimized with respect to, the economic advantages of extruding a polymer composition at the fastest possible speed (for example at high shear rates).

[0006] For any melt-processable thermoplastic polymer composition, there exists a critical shear rate above which the surface of the extrudate becomes rough or distorted and below which the extrudate will be smooth. At shear rates slightly above the critical shear rate, defects in extruded thermoplastics may take the form of "sharkskin" which is a loss of surface gloss that, in more serious manifestations, appears as ridges running more or less transverse to the extrusion direction. At higher shear rates, the extrudate can undergo "continuous melt fracture" becoming grossly distorted. At rates lower than those at which continuous melt fracture is first observed, certain thermoplastics can also suffer from "cyclic melt fracture" in which the extrudate surface varies from smooth to rough. [0007] Other problems encountered during extrusion of thermoplastic polymers include build-up of the polymer at the orifice of the die (known as die build up or die drool), high back pressure during extrusion runs, and excessive degradation or low melt strength of the polymer due to the need to use higher extrusion temperatures to overcome these issues. These problems slow the extrusion process either because the process must be stopped to clean the equipment or because the process must be run at a lower speed.

[0008] Additives for polymer processing (also referred to as “polymer processing additives” or “PPA”) have been used to address such problems. PPAs can reduce melt stagnation at the die and increase the shear rates at which thermoplastic polymers may be extruded without visible melt defects. Fluoropolymers are commonly used as polymer processing additives. In some instances, the performance of fluorinated PPAs can be enhanced by incorporating a “synergist.” Poly(oxyalkylene) polymers such as polyethylene glycol are known to be good synergists when combined with fluoropolymer PPAs.

[0009] Even when extruding thermoplastic polymers using a fluorinated PPA, with or without a synergist, there is an initial period when melt fracture is present resulting in costly production delays and waste. There remains an on-going need to identify additional synergists to reduce the time required to eliminate melt fracture, thereby reducing waste and improving productivity.

[0010] The present inventors have discovered that both di-block copolymers comprising a polylactone block and tri-block copolymers comprising two polylactone end blocks are effective synergists with fluorinated PPAs. In some embodiments, these synergists clear melt fracture more efficiently than traditional poly(oxyalkylene) synergists.

[0011] The synergists of the present disclosure are block copolymers including at least one polylactone block and a comonomer block. Such synergists include (a) di-block copolymers of a polylactone (PL) and a poly(alkyl ether) (PAE), i.e., PL-PAE; (b) di-block copolymers of a PL and a polydialkylsiloxane (PDAS), i.e., PL-PDAS; (c) tri-block copolymers of a PL and a PAE wherein the end blocks are a PL, i.e., PL-PAE-PL; and (d) tri-block copolymers of a PL and a PDAS wherein the end blocks are PL, i.e., PL-PDAS-PL.

[0012] Generally, the polylactone block(s) comprise repeat units according to the general formula - [(CX₂)_n-(C=O)-O]-, where each X is independently selected from the group consisting of H and an alkyl group; and n = 1 to 5. In some embodiments, the polylactone blocks comprise repeat units derived from lactones selected from an alpha-lactone (a-lactone, e.g., acetolactone), a beta-lactone ([3-lactone, e.g., propiolactone); a gamma-lactone (y-lactone, e.g., butyrolactone), a delta-lactone (5-lactone, e.g., valerolactone); and an epsilon-lactone (a-lactone, e.g., caprolactone).

[0013] In some embodiments, each polylactone block of the synergist comprises an average of at least 5, e.g., at least 8, or even at least 10 lactone repeat units. In some embodiments, each PL block of the synergists comprises an average of no greater than 50, e.g., no greater than 40, or even no greater than 35 lactone repeat units. In some embodiments each PL block of the synergists comprises an average of 5 to 50, e.g., 8 to 40, or even 10 to 35 lactone repeat units. [0014] Generally, the poly(alkylene ether) block comprises repeat units of one or more alkylene ethers according to the general formula -[R O]- , where R | is a linear or branched alkyl group. In some embodiments, R1 contains 2-8, e.g., 2-5, carbon atoms. In some embodiments, the poly(alkylene ether) block comprises ethylene oxide repeat units (e.g., PEO), propylene oxide repeat units (PPO) or tetramethylene oxide repeat units (e.g., poly(tetramethylene oxide), also referred to a poly (tetrahydrofuran)). In some embodiments, the poly(alkylene ether) block comprises repeat units of more than one alkylene ether, e.g., a copolymer of ethylene oxide and propylene oxide (PEO/PPO).

[0015] Generally, the polydialkylsiloxane block comprises repeat units according the general formula -[O-Si(R₂)(R₃)]-, where R₂ and R₃ are the same or different alkyl groups. In some embodiments, R₂ and R₃ are the same alkyl group. In some embodiments, R₂ and R₃ comprise one to four carbon atoms. In some embodiments, the dialkylsiloxane is dimethylsiloxane.

[0016] To form a diblock synergist, a monofunctional poly(alkylene ether) may be copolymerized with a lactone. To form triblock synergists, a difunctional PAE may be copolymerized with a lactone to form triblock copolymers with two polylactone end blocks. Generally, the terminal functional groups of the PAEs are not critical. Exemplary functional groups include alcohols and alkyl ethers.

[0017] Similarly, monofunctional poly dialkylsiloxanes may be used to form diblock copolymers with a polylactone block, while difunctional PDAS may be used to form triblock copolymers with two polylactone end blocks. Generally, the terminal functional groups of the PDAS are not critical. Exemplary functional groups include hydroxy groups and alcohols.

[0018] Generally, the synergists are relatively low molecular weight materials. In some embodiments, the number-average MW of the synergist is from 3000 to 12,000 grams/mole, e.g., from 3000 to 10,000 grams/mole. In some embodiments, the MW is at least 4000 or even at least 5000 grams/mole. In some embodiments, the MW is no greater than 10,000 or even no greater than 9,000 g/mole. For example, in some embodiments, the MW of the synergist is from 4000 to 10,000 grams/mole, or even from 5000 to 10,000, or even from 5000 to 9,000 grams per mole.

[0019] Generally, the synergists of the present disclosure may be combined with any known fluorinated polymer processing additive. Exemplary fluorinated PPAs include fluoroelastomer and fluoroplastic copolymers including those derived from one or more of fluorinated olefins such as tetrafluoroethylene (TFE, CF₂=CF₂) and hexafluoropropylene (HFP, CF₃CF=CF₂); perfluorinated vinyl and allyl ethers, halogenated fluoroolefins such as chlorotrifluoroethylene (CTFE); and hydrogencontaining fluoroolefins such as vinylidene fluoride (VDF, CH₂=CF₂). In addition to such fluorinated monomers, in some embodiments, the fluorinated PPAs can include repeat units derived from nonfluorinated olefins such as ethylene (CH₂=CH₂) and propylene (CH₃CH=CH₂).

[0020] In some embodiments, the fluorinated PPA is PVDF or a copolymer of VDF and HFP. In some embodiments, the fluorinated PPA is a copolymer of TFE, HFP and VDF, i.e., a THV copolymer.

Suitable PPAs include those available from 3M Company under the tradename 3M™ DYNAMAR™, from Arkema under the trade name KYNAR®, and from Chemours under the trade name VITON®. [0021] Typically, the selection of the fluorinated PPA depends on several factors including the base thermoplastic polymer, the processing method, and the primary defects being eliminated. For example, when processing high performance polyolefins such a linear low-density polyethylene (LLDPE) and metallocene-catalyzed LLDPE (mLLDPE), melt fracture and die build-up may be the primary defects, particularly when using a blown-film extrusion process. When processing high density polyethylene (HDPE), die build-up and pressure may be the critical problems. Other thermoplastic polymers including but not limited to medium-density polyethylene (MDPE), low-density polyethylene (LDPE), and polypropylene (PP) (including biaxially oriented polypropylene (BOPP)) may also benefit from the addition of fluoropolymer processing additives.

[0022] Depending, in part, on the base thermoplastic polymer(s), the total formulation and the processing conditions, fluorinated PPAs are typically added in amounts ranging from 100 to 2000 ppm (parts by weight relative to the total amount of thermoplastic polymer(s) in the composition). Generally, the lower limit is determined by the minimum amount required to achieve the desired performance advantages, e.g., melt-defect elimination or pressure reduction. Generally, the upper limit is determined by a desire to minimize or avoid impacts on the performance of the final product. For example, if the amount of the fluorinated PPA is too high, it may affect the properties of the extruded article.

[0023] The synergists of the present disclosure can substantially reduce the amount of fluorinated PPA required to achieve the same or better performance. In some embodiments, the weight ratio of synergist to PPA is at least 4:6, e.g., at least 5:5, or even at least 6:4. Generally, the synergists alone (i.e., without the fluoropolymer PPA) are not effective at eliminating melt fracture. Therefore, in some embodiments, the ratio of synergist to PPA is no greater than 9: 1, e.g., no greater than 8:2. In some embodiments, the ratio of synergist to PPA is 4:6 to 9: 1, e.g., 5:5 to 8:2, or even 6:4 to 8:2.

[0024] In some embodiments, the total combined amount of the fluorinated PPA and the synergists of the present disclosure is no greater than 1500 ppm, e.g., no greater than 1200 ppm (parts by weight relative to the base resin). In some embodiments, the total combined amount of the fluorinated PPA and the synergists of the present disclosure is from 200 to 1500 ppm, e.g., from 200 to 1200 ppm, or even 400 to 1200 ppm, inclusive, based on the total weigh of the composition.

[0025] In some embodiments, the composition comprises 20 to 900 parts per million, e.g., 250 to 600 ppm by weight of fluorinated polymer processing agent, based on the total weight of thermoplastic polymers. In some embodiments, the composition comprises 80 to 1350 parts per million, e.g., 800 to 1200 ppm by weight of the synergist, based on the total weight of thermoplastic polymers.

[0026] Examples. Polylactone -containing synergists were prepared as follows.

[0027] Syn-A was prepared by adding 100 g of polyethylene glycol 3400 (PEG 3400) to a 500 milliliter, 3 -necked, round-bottomed flask and heated to 125 °C. Nitrogen gas was bubbled through the molten PEG 3400 for about 30 minutes to drive off any residual water. The temperature was then decreased to 60 °C and 130 g of caprolactone (CL) and 0.1 g Dibutyl Tin Oxide were added. The resulting composition was heated to 130 °C and held for 16 hours under nitrogen. [0028] The theoretical number average molecular weight of the synergist can be calculated from the molecular weight of the PL repeat units, the theoretical average number of PL repeat units, and the MW of the comonomer block. The theoretical average number of PL repeat units can be calculated from the molecular weight of the PL, the MW of the comonomer block, the relative amounts of comonomer block and the lactone added to the polymerization reaction, and the functionality of the comonomer block (i.e., monofunctional leading to a diblock copolymer with only one PL block, or a difunctional leading to a triblock copolymer with two PL blocks).

• Moles comonomer = weight of comonomer block added divided by the molecular weight of the comonomer block

• Moles caprolactone = weight of caprolactone added divided by the molecular weight of the caprolactone

• Molar ratio caprolactone to comonomer = moles of caprolactone divided by moles of comonomer

• Molar ratio of caprolactone block to comonomer = Molar ratio caprolactone to comonomer divided by functionality of the comonomer block (e.g., 1 if the comonomer block is monofunctional and 2 if it is difunctional)

• Number average molecular weight of each caprolactone block = Molar ratio of caprolactone block to comonomer times the caprolactone molecular weight

• Number average molecular weight of the synergist = Number average molecular weight of each caprolactone block times the number of caprolactone blocks plus the molecular weight of he comonomer block.

[0029] The theoretical average number of the lactone repeat units and the number average molecular weight (MW) of the tri -block copolymer were calculated as follows. The use of 100 g of a 3400 g/mole comonomer block (PEG 3400) results in 0.029 moles of the comonomer block (i.e., 100 g/3400 g/mole = 0.0294 moles). Caprolactone has a molecular weight of 114.14 g/mole; thus, the use of 130 g results in 1.14 moles of caprolactone (i.e., 130 g/114. 14 g/mole = 1. 139 moles). Assuming 100% reaction, this results in a molar ratio of lactone to comonomer block of 38.74 (i.e., 1.139/0.0294 = 38.74). As the comonomer block is difunctional, the molar ratio of each PL block to the comonomer block is 19.37 (i.e., 38.74/2 = 19.37). Thus, the theoretical number average MW of each PL block is 2210 grams/mole synergist (i.e., 19.37 x 114.14 g/mole = 2210 g/mole). The theoretical number average molecular weight of the synergist was 7820 grams/mole based on an average of 19.37 repeat units of caprolactone attached on each side of the PEG 3400 diol (i.e., 2210 + 3400 + 2210 = 7820).

[0030] The remaining synergists were prepared in the same manner, with the following modifications. [0031] Syn-B: Polypropylene glycol 4000 (PPG 4000 diol) was used. The amount of caprolactone added was adjusted to obtain a Tri-block copolymer of PPG-4000 with an average of 20 repeat units of CL in the polylactone block on each side of the PPG-4000 diol.

[0032] Syn-C: PEG 750 monol was used instead of the PEG 3400 diol. The amount of caprolactone added was adjusted to obtain a di-block copolymer of PEG 750 with a polylactone block having an average of 30 repeat units of CL. [0033] Syn-D: Polypropylene glycol monobutyl ether 1000 (PPG- 1000) was used. The amount of caprolactone added was adjusted to obtain a di -block copolymer of PPG- 1000 with a polylactone block having an average of 25 repeat units of CL.

[0034] Syn-E: Polydimethylsiloxane mono-hydroxyl terminated X-22-170DX (from Shin-Etsu) was used. The amount of caprolactone added was adjusted to obtain a di-block copolymer of PDMS-with a polylactone block having an average of 23.9 repeat units of CL.

[0035] Syn-F: Polydimethylsiloxane mono-hydroxyl terminated X-22-170BX (from Shin-Etsu) was used. The amount of caprolactone added was adjusted to obtain a di-block copolymer of PDMS-with a polylactone block having an average of 17.3 repeat units of CL.

[0036] Syn-G: Polydimethylsiloxane di-hydroxyl terminated KF-6002 (from Shin-Etsu) was used.

The amount of caprolactone added was adjusted to obtain a tri-block copolymer of PDMS-with an average of 10.5 repeat units of CL in the on each side of the PDMS diol.

[0037] Syn-H: Polydimethylsiloxane di-hydroxyl terminated KF-6003 (from Shin-Etsu) was used.

The amount of caprolactone added was adjusted to obtain a tri-block copolymer of PDMS-with an average of 10.5 repeat units of CL in the polylactone block on each side of the PDMS diol.

[0038] Syn-E Polyethylene glycol 8000 (PEG-8000 diol) was used. The amount of caprolactone added was adjusted to obtain a Tri-block copolymer of PEG-8000 with an average of 20 repeat units of CL in the polylactone block on each side of the PEG-8000 diol.

[0039] Syn-J: Poly(tetramethylene oxide) (PTMG-2000 diol) was used. The amount of caprolactone added was adjusted to obtain a Tri-block copolymer of PTMG-2000 with an average of 20 repeat units of CL in the polylactone block on each side of the PTMG-2000 diol.

[0040] The characteristics of these synergists are summarized in Table 1. The average molecular weights of the blocks were calculated based on the average number of repeat units. Thus, 2202/3400/2202 refers to a triblock copolymer with 2202 MW PL end-blocks and a 3400 MW copolymer midblock (CB). The diblock copolymers are reported as the MW of the polylactone (PL) end block followed by the MW of the copolymer block (CB). Thus, 3423/750 refers to a diblock copolymer with a 3423 MW PL block and 750 MW copolymer block.

Table 1: Synergist compositions.

[0041] To beter control the amounts of the synergist added, each synergist was compounded to form a master batch with the base polymer as follows. First, 60 grams of the synergist were blended in a Henschel mixer with 120 grams of LLDPE (2MI LLDPE, EM 1002.09 available from Exxon Mobil). Then, 180 grams of this synergist/LLDPE mixture were added to a bag containing 2815 grams of the LLDPE resin, 3.0 grams of a stabilizer (IRGANOX® B900 from BASF), and 2.1 grams of zinc stearate. The contents of the bag were shaken vigorously to form a master batch of LLDPE containing 2.0% by weight of the synergist.

[0042] Each master batch was then fed to a laboratory scale, intermeshing, counter rotating, unvented, air cooled, conical twin screw (HaakeBuchler Rheomix TW-100) with a front inside diameter of 20 millimeters. The mixture was gravity fed to the throat of the extruder, exposed to air, at a rate of 50 grams/minutes. The temperatures of the three-barrel zones (feed, metering, mixing), and die zone were 170/190/200/200 °C, respectively. The extruder was run at 150 RPM for the first “compounding” pass. A second pass was run with the same temperature profile but at 90 RPM while flood feeding the material to form pellets of the master batch material. A four-minute “purge” of material was discarded at the beginning each pass.

[0043] Pellets of a control sample of 2 wt.% PEG 8000 synergist were prepared using the same mixing and extrusion conditions. The masterbatch contained 60 grams of the PEG, 2935 grams of the LLDPE, 3.0 grams of the stabilizer, and 2.1 grams of zinc stearate.

[0044] Pellets of a 3 wt.% master batch of a fluoropolymer polymer processing additive were prepare using the same mixing and extrusion conditions. The masterbatch contained 90 grams of the fluorinated PPA (3M™ DYNAMAR™ FX 9613 PPA, from 3M Company), 2905 grams of the LLDPE, 3.0 grams of the stabilizer, and 2.1 grams of zinc stearate.

[0045] The synergists were tested at 1000 ppm without the fluoropolymer PPA. Testing was done by diluting the synergist master batches to a target level of 1000 ppm of synergist in the base polymer at 210 °C, 0.9 millimeter gap, 14 L/D, 10.5 kilograms/hour, and 220/s, in combination with 6000 ppm of an antiblocking agent (ABT 7500 from Ampacet Corporation, MB # 101558) and 1000 ppm of a slip agent (erucamide from Ampacet Corporation, MB # 10090).

[0046] The performance of the synergists was evaluated by measuring the time required to reduce melt fracture in a blown film line. The base thermoplastic polymer was LLDPE (MARFLEX® 7109, 0.9 MI ZN LLDPE, available from Chevron Philips Chemicals). Trials were conducted using a blown film line with a 40 mm, 30/1, extruder from Labtech Engineering Co. LTD. The die was of spiral design with a 40-mm diameter and 0.9 mm die gap (36 mil). [0047] The base thermoplastic polymer was extruded for thirty minutes to clear the extruder before beginning the addition of the synergist. The pressure was recorded every ten minutes and a sample of film was collected. The film was examined for the presence of melt fracture (MF), which was expressed as a percentage of the film area covered with MF.

[0048] The decrease in pressure as a function of time for samples prepared with only the synergist (i.e., without the fluoropolymer PPA) was tested. The pressure reductions, reported as the difference between the pressure and the initial pressure and dividing it by the initial pressure, are shown in Table 2. Generally, little or no pressure decrease was observed. Also, alone, none of the synergists eliminated melt fracture in the LLDPE film.

Table 2: Pressure reduction for Synergists without fluoropolymer (% of initial pressure).

[0049] The synergists were then tested in combination with a fluoropolymer processing additive. Testing was done by diluting the synergist master batches to a target level of 700 ppm of synergist and 300 ppm of fluoropolymer processing additive in the base polymer in combination with 6000 ppm of an anti -blocking agent (ABT 7500 from Ampacet Corporation, MB # 101558) and 1000 ppm of a slip agent (erucamide from Ampacet Corporation, MB # 10090), using the process described above.

[0050] The performance of the synergists in combination with the fluoropolymer PPA was evaluated by measuring the time required to reduce melt fracture in a blown film line. The base thermoplastic polymer was LLDPE (MARFLEX® 7109, 0.9 MI ZN LLDPE, available from Chevron Philips Chemicals). Trials were conducted using the blown film line described above. The time corresponding to the disappearance of the last band of MF, i.e., the time to clear melt fracture (TTC) was recorded, at which point the test was stopped. If any MF was remaining at the end of two hours, the test was stopped, and the final MF level recorded. In such cases, the TTC was estimated from the shape of the curve. The time to reach 50% melt fracture (50% MF) was obtained from a gaussian fit to the data.

[0051] The time (minutes) required to achieve a 50% reduction in melt fracture (50% MF) and the time (minutes) to clear melt fracture (TTC) are shown in Table 3. The 50% MF and TTC times are also shown as a percentage of the times required when using the PEG control synergist (reported as % of PEG). Table 3: Time in minutes to achieve a 50% reduction in melt fracture and total time to clear.

[0052] As shown, the polylactone-based diblock and triblock copolymers of the present disclosure substantially reduce the time to reduce melt fractures when used in combination with a fluoropolymer PPA. In addition, the polylactone -based synergists can be more effective than standard poly(oxyalkylene) synergists such as PEG. Syn-I, having a molecular weight of greater than 12,000 gram/mole never cleared melt fracture (Comparative Example CE-2).

[0053] The decrease in pressure as a function of time for samples prepared with the synergists in combination with a fluoropolymer PPA was tested. The pressure reductions, reported as the difference between the pressure and the initial pressure and dividing it by the initial pressure, are shown in Table 4.

Table 4: Pressure reduction for Synergists with a fluorinated PPA (% of initial pressure).

As shown, the combination of the polylactone -based synergists with a fluoropolymer PPA can lead reductions in extrusion pressure comparable to traditional synergists like PEG.

[0054] Although not effective alone, the polylactone-based synergists can significantly reduce the amount of fluoropolymer PPA required when melt-processing thermoplastics such as polyolefins. For example, such synergists can reduce the amount of fluorinated PPA required to achieve the same or shorter times to reduce melt fracture, even relative to the use of traditional synergists such PEG. In addition, the polylactone-based synergists can reduce the extrusion pressure enabling higher processing speeds.

[0055] These polylactone-based synergists can be used to improve the melt-processing operations such as extrusion casting and extrusion melt-blowing operations. Although not limited to such compositions, the polylactone-based synergists may be particularly effective when processing polyolefin- based compositions, i.e., compositions where in at 70% by weight of the thermoplastic polymers in the melt-pressed composition are polyolefins. In some embodiments, at least 80%, e.g., at least 90%, or even at least 99% by weight, based on the total weight of all thermoplastic polymers in the composition, are polyolefins.

Claims

What is Claimed is:

1. A composition comprising at least one thermoplastic polymer, a fluorinated polymer processing additive and a synergist, wherein the synergist is a block copolymer comprising at least one polylactone block and a comonomer block, and the weight ratio of the synergist to fluorinated polymer processing additive is from 4:6 to 9: 1, inclusive.

2. The composition of claim 1, wherein the comonomer block is selected from the group consisting of poly(alkylene ether) and polydialkylsiloxane.

3. The composition of claim 2, wherein the comonomer block is a poly(alkylene ether).

4. The composition of claim 3, wherein the poly(alkylene ether) consists of repeat units selected from the group consisting of ethylene oxide, propylene oxide, tetramethylene oxide, and combination thereof.

5. The composition of claim 2, wherein the comonomer block is polydialkylsiloxane.

6. The composition of claim 5, wherein the polydialkylsiloxane is polydimethylsiloxane.

7. The composition of any one of the preceding claims, wherein the synergist is a diblock copolymer.

8. The composition of claim 7, wherein the polylactone block of the diblock copolymer comprises 5 to 40 lactone repeat units.

9. The composition of any one of claims 1 to 6, wherein the synergist is a triblock copolymer comprising two polylactone end blocks and a midblock comprising the comonomer.

10. The composition of claim 9, wherein each polylactone end block of the triblock copolymer comprises 5 to 40 lactone repeat units.

11. The composition of any one of the preceding claims, wherein the number-average molecular weight of the synergist is from 3000 to 12,000 grams/mole, inclusive, preferably 3000 to 10,000 grams/mole, inclusive.

12. The composition of any one of the preceding claims, wherein at least one thermoplastic polymer comprises a polyolefin.

13. The composition of claim 12, wherein at 70% by weight, based on the total weight of the thermoplastic polymers, are polyolefins.

14. The composition of claim 12 or 13, wherein at least one polyolefin is a polyethylene.

15. The composition of claim 14, wherein the polyethylene is a linear low-density polyethylene.

16. The composition of any one of the preceding claims, wherein the fluorinated polymer processing additive is copolymer comprising repeat units of at least two of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride.

17. The composition of claim 16, wherein the fluorinated polymer processing additive is a copolymer comprising repeat units of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride.

18. The composition of any one of the preceding claims, wherein the composition comprises 200 to 1500 parts per million by weight of the synergist and the fluorinated polymer processing agent combined, based on the total weight of the thermoplastic polymers.

19. The composition of claim 18, wherein the composition comprises 20 to 900 parts per million by weight of fluorinated polymer processing agent, based on the total weight of thermoplastic polymers.

20. The composition of claim 18, wherein the composition comprises 80 to 1350 parts per million by weight of the synergist, based on the total weight of thermoplastic polymers.

21. A method of reducing melt fracture comprising combining the fluorinated polymer processing additive, the synergist and the thermoplastic polymer to form the composition of any one of the preceding claims and extruding the composition to form an article.

22. The method of claim 21, wherein extruding the composition comprises melt-blowing the composition.

23. The method of claim 21 or 22, wherein the article comprises a film.