Melt flow additives for polycarbonates and other engineering resins

Abstract

Disclosed are compositions comprising a polycarbonate or an engineering resin and a branched polymer that is a reaction product of reactants comprising one or more monoethylenically unsaturated ester monomers, a chain transfer agent in an amount of 0.1 wt% to 10 wt%, and a crosslinking agent in an amount of 0.1 wt% to 10 wt%, wherein wt% is based on the total amount of reactants, with the proviso that the amount of crosslinking agent in moles is less than the effective amount of chain transfer agent in moles, and articles thereof.

Description

TECHNICAL FIELD

[0001] The field of the present invention is compositions comprising polycarbonate or other engineering resins and articles made from such compositions. BACKGROUND

[0002] Various indoor and outdoor products benefit from the use of transparent and / or weatherable plastic materials. Fluoropolymers and thermoplastic polyurethanes provide these properties, but are too expensive for many end uses.

[0003] Polycarbonate materials tend to be highly viscous, which makes processing in certain applications challenging. Conventional additives can have an adverse effect on the light transmission of polycarbonate compositions. SUMMARY

[0004] Disclosed herein is a composition comprising a resin selected from the group consisting of a polycarbonate resin and an engineering resin, and a branched polymer, wherein the resin does not comprise a multi-stage acrylic resin, and the branched polymer is a reaction product of reactants comprising one or more mono-olefinically unsaturated ester monomers, a chain transfer agent in an amount of 0.1 wt% to 10 wt%, and a crosslinking agent in an amount of 0.1 wt% to 10 wt%, wherein the wt% is based on the total amount of the reactants, with the proviso that the amount of the crosslinking agent in moles is less than the effective amount of the chain transfer agent in moles. The branched polymer is not crosslinked.

[0005] Also disclosed herein is an article comprising the above-mentioned composition. BRIEF DESCRIPTION OF DRAWINGS

[0006] Figure 1 is a chart showing the results of weatherability testing of compositions according to embodiments of the invention.

[0007] Figure 2 shows the haze values of compositions according to embodiments of the invention. DETAILED DESCRIPTION

[0008] Disclosed herein is a composition comprising a resin selected from the group consisting of a polycarbonate resin and an engineering resin, and a branched polymer.

[0009] The resin is selected from the group consisting of a polycarbonate resin and an engineering resin. As used herein, the term "polycarbonate" includes homopolycarbonates (wherein the repeating units in the polycarbonate are the same) and polycarbonate copolymers (which comprise different repeating units in the polycarbonate). As used herein, the phrase "engineering resin" refers to a resin selected from the group consisting of polycarbonate-polyester blends, poly(methyl methacrylate), polyamides, poly(alkylene terephthalate), and blends thereof. Preferably, the resin is selected from the group consisting of a polycarbonate resin and a poly(methyl methacrylate) resin. More preferably, the resin is a polycarbonate resin.

[0010] Preferably, the resin does not include a multi-stage acrylic resin. As used herein, the phrase "does not include a multi-stage acrylic resin" means that the resin component of the composition does not include a multi-stage acrylic resin, i.e., an acrylic resin that includes multiple different acrylic components. The composition includes a branched polymer as described below and optionally an impact modifier.

[0011] The branched polymer is a reaction product of reactants including one or more monoethylenically unsaturated ester monomers, a chain transfer agent in an amount of 0.1 wt% to 10 wt%, and a crosslinking agent in an amount of 0.1 wt% to 10 wt%, where wt% is based on the total amount of reactants. The branched polymer is not crosslinked. To avoid crosslinking, the amount of crosslinking agent is no greater than the amount of chain transfer agent. Thus, according to certain embodiments, the number of moles of crosslinking agent is no greater than or less than the number of moles of chain transfer agent. According to certain embodiments, the weight percent of crosslinking agent is less than the weight percent of chain transfer agent.

[0012] Suitable monoethylenically unsaturated ester monomers for making branched polymers according to certain embodiments can have the structure R'-C(0)0-R, where R is a hydrocarbyl group (e.g., an alkyl group or an aryl group), and R' is a monoethylenically unsaturated aliphatic group having at least 2 or 3 carbon atoms. According to certain embodiments, R is an alkyl group having at least 1 or 2 or 3 carbon atoms. According to certain embodiments, R is an alkyl group having no more than 12 or 10 or 8 or 6 or 5 carbon atoms. According to certain embodiments, R is an aryl group having from 6 to 12 carbon atoms. According to certain embodiments, R' has no more than 6 carbon atoms. Examples of suitable monomers include butyl acrylate, ethylhexyl acrylate, ethyl acrylate, methyl methacrylate, butyl methacrylate, (meth)cydohexyl (meth)acrylate, cyclopentyl methacrylate, tetrahydrofurfuryl methacrylate, and benzyl (meth)acrylate. A combination of two or more such monoethylenically unsaturated ester monomers can be used. For example, a combination of methyl methacrylate and butyl methacrylate can be used. For example, the amount of methyl methacrylate can be at least 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, or 80 wt% of the reactants, and can be, for example, less than 99.8 wt%, 99 wt%, 98 wt%, 97 wt%, 96 wt%, 95 wt%, 90 wt%, 85 wt% of the reactants. The second monoethylenically unsaturated ester monomer (e.g., butyl acrylate) can be 0 wt% or greater than 0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt% and less than 60 wt%, 50 wt%, 40 wt%, 30 wt%, 20 wt%, or 10 wt% of the reactants. In certain embodiments, additional monoethylenically unsaturated ester monomers can be used. In such embodiments, the combination of the second and additional monoethylenically unsaturated monomers is greater than 0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt% and less than 60 wt%, 50 wt%, 40 wt%, 30 wt%, 20 wt%, or 10 wt% of the reactants.

[0013] According to certain embodiments, one or more additional mono-unsaturated addition polymerizable (e.g., monoethylenically unsaturated) monomers can be included. For example, styrene or acrylonitrile can be added. Such additional amounts are preferably less than 10 wt% or 5 wt% based on the weight of the reactants.

[0014] The reactants also include a chain transfer agent (CTA). The chain transfer agent can be any compound known or discovered to be useful as a chain transfer agent in the polymerization of acrylate or methacrylate monomers. For example, a mercaptan chain transfer agent can be used. Examples of such mercaptan CTA include monofunctional and multifunctional mercaptans. Monofunctional mercaptans include, but are not limited to, propanethiol, butanethiol, hexanethiol, octanethiol, dodecanethiol, mercaptoacetic acid, mercaptopropionic acid, mercaptoacetic acid alkyl esters (e.g., mercaptoacetic acid-2-ethylhexyl ester or octyl mercaptoacetate), mercaptoethanol, mercaptoundecanoic acid, thiolactic acid, thiobutyric acid. Multifunctional mercaptans include tri-functional compounds such as trimethylolpropane tri(3-mercaptopropionate); tetra-functional compounds such as pentaerythritol tetra(3-mercaptopropionate), pentaerythritol tetrathioglycolate, pentaerythritol tetrathiolactate, pentaerythritol tetrathiobutyrate; hexa-functional compounds such as dipentaerythritol hexa(3-mercaptopropionate), dipentaerythritol hexathioglycolate; octa-functional mercaptans such as tripentaerythritol octa(3-mercaptopropionate), tripentaerythritol octathioglycolate. The use of multifunctional mercaptans is a useful method of increasing the degree of branching of the polymer. Optionally, the chain transfer agent can comprise a mixture of more than one type of compound. According to one embodiment, the CTA is selected from butyl 3-mercaptopropionate (BMP) and pentaerythritol tetra(3-mercaptopropionate) (PETMP) When the CTA is PETMP, about a quarter molar amount of CTA can be used.

[0015] Alternative chain transfer agents can be any substance known to reduce molecular weight in the conventional free radical polymerization of vinyl monomers. Examples include sulfides, disulfides, halogen-containing substances. In addition, catalytic chain transfer agents such as cobalt complexes, e.g., cobalt (II) chelates such as cobalt porphyrin compounds are useful chain transfer agents of the present invention. Suitable cobalt chelates are known in the art and described in WO 98 / 04603. A particularly suitable compound is bis(borondifluorodimethylglycolate) cobaltate (II), also known as CoBF. Catalytic chain transfer agents can be used at relatively low concentrations compared to conventional mercaptan chain transfer agents, e.g., <0.5 wt.%, preferably <0.1 wt.% (based on monofunctional monomers), as they are typically highly effective at low concentrations. Cobalt complex-based catalytic chain transfer compounds can be used very effectively at concentrations of less than 0.05 wt.% (500 ppm), e.g., 0.0001 wt.% to 0.01 wt.% (1 ppmw to 100 ppmw) based on the monofunctional monomers in the polymerization process of the present invention, resulting in soluble branched polymers.

[0016] The amount of chain transfer agent is at least 0.1 wt% or 0.5 wt% or 1 wt%, based on the total weight of the reactants. According to some embodiments, the amount of chain transfer agent is no more than 10 wt% or 8 wt% or 6 wt% or 5 wt%, based on the total weight of the reactants.

[0017] The reactants also include a crosslinking agent. The inclusion of a crosslinking agent provides branching. However, the amount of crosslinking agent must be controlled so that the polymer does not crosslink. Preferably, the weight percent of the crosslinking agent is less than or equal to the weight percent of the chain transfer agent. Preferably, the weight ratio of chain transfer agent to crosslinking agent is in the range of 1 : 1 or 1.5: 1 to 10: 1, based on the weight of the chain transfer agent to the weight of the crosslinking agent. Alternatively, the mole percent of the crosslinking agent is less than the effective mole percent of the chain transfer agent. Preferably, the mole ratio of chain transfer agent to crosslinking agent is at least 1.2: 1 or 1.4: 1 or 1.5: 1 or 1.7: 1 or 2: 1 or 4: 1, based on the effective amount of chain transfer agent in moles to the amount of crosslinking agent in moles. As used herein, the “effective amount of chain transfer agent in moles” is based on the number of functional groups on the chain transfer agent. For example, the number of functional groups of PETMP is four times that of BMP. Thus, the molar amount of PETMP would be four times the effective amount of the similar molar amount of BMP, i.e., the effective amount of PETMP is four times the actual amount. Similarly, the term “effective mole percent” is also based on the number of functional groups in the chain transfer agent. According to one embodiment, the mole ratio of chain transfer agent to crosslinking agent is less than 20: 1 or 15: 1 or 10: 1, based on the effective amount of chain transfer agent in moles to the amount of crosslinking agent in moles.

[0018] The crosslinking agent can be any multifunctional unsaturated monomer, i.e., any monomer having two or more unsaturated groups available for polyaddition. Examples of suitable difunctional monomers include ethylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, tripropyleneglycol di(meth)acrylate, butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, allyl (meth)acrylate, divinyl benzene and derivatives thereof. Examples of trifunctional include tripropyleneglycol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate. Tetrafunctional monomers such as pentaerythritol tetra(meth)acrylate and hexafunctional monomers such as dipentaerythritol hexa(meth)acrylate can also be used. Optionally, the multifunctional monomer can comprise a mixture of more than one multifunctional compound. According to one embodiment, the crosslinking agent is 1,4-butanediol dimethacrylate (BGDMA).

[0019] The amount of crosslinker according to some embodiments is at least 0.1 wt% or 0.5 wt% or 1 wt%, based on the total weight of reactants. According to some embodiments, the amount of crosslinker is no more than 10 wt% or 8 wt% or 6 wt% or 5 wt%, based on the total weight of reactants.

[0020] According to certain embodiments, the crosslinker is BGDMA and the chain extender is BMP. According to one embodiment, the acrylate monomer (e.g., methyl methacrylate) is present in an amount of 90 wt% to 99 wt%, the amount of BGDMA is in the range of 1 wt% or 2 wt% to 4 wt% or 3 wt%, and the amount of BMP is in the range of 1 wt% or 2 wt% or 3 wt% to 7 wt% or 6 wt%, based on the total weight of acrylate monomer, BGDMA, and BMP.

[0021] The branched polymer can be prepared using any free radical polymerization method, for example, solution, suspension, emulsion, and bulk polymerization methods can all be used. For example, conventional emulsion polymerization can be used.

[0022] A surfactant or emulsifier can be used. Examples of emulsifiers include nonionic, anionic, and cationic emulsifiers.

[0023] Suitable nonionic emulsifiers are araliphatic or aliphatic nonionic emulsifiers, examples being ethoxylated mono-, di- and trialkylphenols (degree of ethoxylation: 3 to 50, alkyl group: C4-C 10 , ethoxylates of long-chain alcohols (degree of ethoxylation: 3 to 100, alkyl group: C8-C 36 ), and polyethylene oxide / polypropylene oxide homopolymers and copolymers. These can contain alkylene oxide units which are copolymerized in a random distribution or in block form. Highly suitable are, for example, ethylene oxide / propylene oxide block copolymers. Preference is given to using ethoxylates of long-chain alkanols (alkyl group C1-C 30 , average degree of ethoxylation 5 to 100), and among these, those having a linear C 12 -C 20 alkyl group and an average degree of ethoxylation of 10 to 50, and ethoxylated monoalkylphenols.

[0024] Suitable anionic emulsifiers are alkyl sulfates (alkyl group: C8-C 22 ), sulfuric monoesters with ethoxylated alkanols (degree of ethoxylation: 2 to 50, alkyl group: C 12 -C 18 ) and ethoxylated alkylphenols (degree of ethoxylation: 3 to 50, alkyl group: C4-C9), alkyl sulfonic acids (alkyl group: C 12 -C 18 ) and alkylaryl sulfonic acids (alkyl group: C9-C 18alkali metal and ammonium salts. Other suitable emulsifiers are found in Houben-Weyl, Methoden der organischen Chemie, Volume XIV / 1, Makromolekulare Stoffe, Georg-Thieme-Verlag, Stuttgart, 1961, pages 192-208. In addition, suitable as anionic emulsifiers are bis(phenylsulfonic acid)ethers and their alkali metal or ammonium salts, which carry a C4-C 24 alkyl groups on one or both aromatic rings. These compounds are known, for example, from US Patent No. 4,269,749 and can be obtained, for example, as Dowfax 9N38® (Dow Chemical Company). TM 2A1 (Dow Chemical Company) are commercially available.

[0025] Suitable cationic emulsifiers are preferably quaternary ammonium halides, such as trimethylcetylammonium chloride, methyltrioctylammonium chloride, benzyltriethylammonium chloride or N-C6-C 20 quaternary ammonium compounds of -alkylpyridines, -morpholines or -imidazoles, such as N-laurylpyridinium chloride.

[0026] Other suitable surfactants or emulsifiers include phosphate ester surfactants and emulsifiers, such as RHODAFAC® phosphate ester surfactants and emulsifiers available from Solvay, such as RHODAFAC® RS 610. phosphate ester surfactants and RHODAFAC phosphate ester emulsifiers available from Solvay, such as RHODAFAC RS 610.

[0027] The amount of emulsifier (or surfactant) can be at least 0.01 wt% or 0.1 wt% to 10 wt% or 5 wt%, based on the amount of monomers to be polymerized.

[0028] An initiator can be used. Examples of initiators include those that can be initiated by any suitable free radical generating method, such as by thermal induced decomposition of a thermal initiator such as an azo compound, a peroxide or a peroxyester. Thus, the polymerization mixture also preferably comprises a polymerization initiator, which can be any of those known and conventionally used in free radical polymerization reactions. Examples of azo initiators include azobis(isobutyronitrile) (AIBN), azobis(2-methylbutyronitrile), azobis(2,4-dimethylvaleronitrile), azobis(4-cyanopentanoic acid). Examples of peroxide and peroxy initiators include hydrogen peroxide, sodium peroxide, potassium peroxide, t-butyl hydroperoxide, cumene hydroperoxide, dilauroyl peroxide, t-butyl peroxyneodecanate, dibenzoyl peroxide, cumyl peroxide, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxydiethylacetate and t-butyl peroxybenzoate. Examples of additional initiators include ammonium and / or alkali metal persulfates, sodium perborate, perphosphoric acid and its salts, potassium permanganate, and ammonium or alkali metal salts of peroxodisulfuric acid, exemplified by alkali metal peroxodisulfates or ammonium peroxodisulfate, diacetyl peroxide, dibenzoyl peroxide, succinyl peroxide, di-t-butyl peroxide, t-butyl perbenzoate, t-butyl perpivalate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxymaleate, cumene hydroperoxide, diisopropyl peroxydicarbonate, bis(o-toluoyl) peroxide, didecanoyl peroxide, dioctanoyl peroxide, dilauroyl peroxide, t-butyl peroxyisobutyrate, t-butyl peroxyacetate, di-t-amyl peroxide, t-butyl hydroperoxide, azobisisobutyronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride or 2,2'-azobis(2-methylbutyronitrile). Mixtures of these initiators are also suitable. As initiators, it is also possible to use reduction / oxidation (i.e. redox) initiator systems. Redox initiator systems consist of at least one (usually inorganic) reducing agent and one organic or inorganic oxidizing agent. The oxidizing component includes, for example, emulsion polymerization initiators already specified above. The reducing component includes, for example, alkali metal salts of sulfurous acid, such as sodium sulfite, sodium bisulfite; alkali metal salts of disulfurous acid, such as sodium disulfite; hydrogensulfite addition compounds of aliphatic aldehydes and ketones, such as acetone hydrogensulfite; or reducing agents such as hydroxymethanesulfmic acid and its salts, or ascorbic acid. Redox initiator systems can be used together with soluble metal compounds whose metal component is capable of existing in multiple valence states. Typical redox initiator systems are, for example, ascorbic acid / iron(II) sulfate / sodium peroxodisulfate, t-butyl hydroperoxide / sodium disulfite, t-butyl hydroperoxide / sodium hydroxymethanesulfmate. The individual components, for example the reducing component, can also be mixtures, for example mixtures of sodium hydroxymethanesulfmate and sodium disulfite.

[0029] The amount of initiator is typically at least 0.01 wt% or 0.05 wt% or 0.01 wt% to 10 wt% or 5 wt% or 3 wt%, based on all monomers to be polymerized.

[0030] The branched polymer is not crosslinked. This can be demonstrated, for example, by assessing the solubility of the polymer in a solvent such as tetrahydrofuran. Crosslinked polymers will not be soluble.

[0031] The branched polymers according to certain embodiments are characterized by a polymer branching ratio g' of less than 1, 0.95, 0.9, 0.8. According to some embodiments, g' is at least 0.5 or 0.6 or 0.7. The polymer branching ratio (g') is calculated by comparing the intrinsic viscosity ([η]branched) of the branched polymer measured at each elution volume increment to the intrinsic viscosity ([η]linear) of a linear polymer having the same molecular weight (M) in gel permeation chromatography (GPC) analysis (Equation 1). For linear polymers, the g' value is equal to 1, and for branched polymers, g' is less than 1. 支化

[0032]

[0033] Molecular weight analysis: Polymer absolute molecular weight (M w , M n ), PMMA relative molecular weight (M w_PMMA , M n_PMMA ), intrinsic viscosity ([η] w , [η] n ​) and branching ratio (g') can be measured by gel permeation chromatography with online multi-angle light scattering (MALS) detector, viscometer (VS), and differential refractive index (dRI) detectors. For example, GPC instrument setup can include an Agilent 1200 series HPLC system (degasser, pump, autosampler, and column oven), Wyatt HELEOS II MALS detector, Wyatt ViscoStar II viscometer, and Wyatt T-rEX dRI detector. Polymer separation can be performed on a column set, for example, with two PLgel mixed B LS columns (10 pm particle size, 7.5 x 300 mm length), using tetrahydrofuran (THF) as mobile phase at a flow rate of 1 mL / min. Column oven temperature is set to 30 °C. A set of 10-point PMMA standards (Agilent EasiCal PM-1) is used to calibrate the GPC columns and provide PMMA relative molecular weights. Absolute molecular weights are obtained from the MALS detection using the Zimm form, and intrinsic viscosity data are obtained from the viscometer. High molecular weight fraction data (PMMA relative molecular weight greater than 6500 Da) are used to calculate average g' values. For consistency in g' calculation, using a linear PMMA model from the Mark-Houwink equation (Equation 2, where K = 0.0383 mL / g and a = 0.581 for samples in Table 2 that do not contain BA, and K = 0.03044 mL / g and a = 0.615 for polymers in Table 2 that contain BA), using M data from the MALS detection, ([h]linear) in Equation 1 is obtained.

[0034] [η] = KM α (Equation 2)

[0035] The weight average molecular weight M of the branched polymer measured by GPC w Preferably in the range of at least 8000 g / mol or 10,000 g / mol or 15,000 g / mol or 20,000 g / mol. Preferably, the weight average molecular weight is not more than 100,000 g / mol or 80,000 g / mol. The number average molecular weight M of the branched polymer measured by GPC n Preferably at least 3000 g / mol or 4000 g / mol or 5000 g / mol. Preferably, the number average molecular weight is not more than 50,000 g / mol or 40,000 g / mol or 30,000 g / mol or 20,000 g / mol.

[0036] Preferably, the branched structure is a dendritic structure.

[0037] Preferably, the amount of branched polymer in the composition is at least 1% by weight, 3% by weight, 5% by weight, or 10% by weight. The composition may be in concentrated form and then mixed with a polycarbonate or engineering resin polymer to obtain the desired amount of branched polymer in the composition being processed (e.g., extrusion, injection molding). In concentrated form, the amount of branched polymer may constitute a large portion of the composition, for example, up to 60% by weight, 50% by weight, or 40% by weight. For use in processing to obtain the benefit of a higher melt flow index (lower viscosity), according to some embodiments, the composition may contain up to 30% by weight, 25% by weight, or 20% by weight of branched polymer. The branched polymer is soluble (miscible) in the polycarbonate or engineering resin in the amount used.

[0038] The composition may also contain additional additives required for the final product. Examples of such additives include UV light stabilizers and antioxidants. In some embodiments, the additives are selected to maintain the transparency of the composition. Examples of UV light stabilizers include benzophenone, benzotriazole, triazine, benzoxazinone, hindered amine light stabilizers (HALS), and hindered benzoate esters. Examples of commercially available UV light stabilizers include Cyasorb Light Absorber, Light Stabilizer, and CyasorbCynergy Solution from Solvay; TINUVIN from BASF; LowLite from Chemtura; OnCap from PolyOne; and LightStabilizer 210 from EIdu Pont de Nemours and Company of Delaware, USA. Examples of antioxidants include phenolic antioxidants, and combinations of phenolic antioxidants with phosphites, thioethers, or organosulfur compounds. Phenolic antioxidants include fully sterically hindered phenols and partially sterically hindered phenols; and sterically hindered amines, such as tetramethylpiperidine derivatives. Suitable phenolic antioxidants include vitamin E and IRGANOX (purchased from BASF). TM 1010. IRGANOX TM 1010 includes pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate).

[0039] In certain applications, it is desirable for the composition to have light transmission. It has been surprisingly found that branched polymer additives can be used to form polycarbonate compositions having high light transmission or low haze. According to certain embodiments, the composition is haze-free. Preferably, the haze-free composition has a haze of less than 5% as measured by light transmission using suitable instrumentation, such as a BYK Haze Guard Plus, according to ASTM D1003. Preferably, the haze-free composition has a haze of less than 4%, more preferably less than 3%, even more preferably less than 2% as measured by light transmission. When a haze-free composition is desired, the composition preferably does not include an impact modifier.

[0040] When light transmission is not required, the composition preferably includes an impact modifier.

[0041] The composition can be prepared by a conventional melt compounding process of the components. The above compositions were processed using a 26 mm laboratory co-rotating twin-screw extruder equipped with a 5 mm die, L / D of 27, under the conditions listed in Table 1 below. The resulting strands of molten resin were cooled through a water bath. The cooled strands were chopped into small pellets, which were then injection molded into test bars for mechanical property testing.

[0042] Table 1

[0043]

[0044] Due to the advantageous melt flow index, the composition can be used for extrusion and injection molding applications.

[0045] Examples

[0046] Synthesis of Branched Polymer Additive #1

[0047] Emulsion polymerization was carried out in a 5 liter 4 necked round bottom flask equipped with a mechanical stirrer, heating mantle, thermometer, temperature controller and N2inlet. The reactor was charged with 1063 parts of deionized water, 6.01 parts of A18sulfate surfactant (42% aqueous solution) and 0.091 parts of Fe-EDTA complex (as Sequestrene). The contents of the reactor were heated to 75°C under N2purge. A monomer emulsion was prepared in a separate vessel with 238.5 parts of deionized water, 24.04 parts of A18sulfate surfactant (42% aqueous solution), 50 parts of butyl acrylate (BA), 875 parts of methyl methacrylate (MMA), 50 parts of butyl 3-mercaptopropionate (BMP) and 25 parts of 1,4 butanediol dimethacrylate (BGDMA). Mechanical stirring was used to achieve emulsification. The redox initiator system consisted of 2 separate solutions. The first was a 2% (wt) aqueous solution of t-butyl hydroperoxide (t-BHP) (oxidizer) and the second was a 2% (wt) aqueous solution of sodium formaldehyde sulfoxylate (SFS) (reducing agent), both for a total of 80 parts. 94.69 parts of the monomer emulsion was added to the reactor vessel and after 1 minute (time zero) the feeding of both the t-BHP and SFS solutions was started simultaneously at 0.89 parts / minute (both for a feeding time of 90 minutes). The reactor temperature was maintained at 75°C throughout the polymerization. After 15 minutes the remaining monomer emulsion was fed at 19.46 parts / minute (for a feeding time of 60 minutes). At the end of the monomer feed (total reaction time of 75 minutes from time zero) the t-BHP and SFS were fed for an additional 15 minutes (total reaction time of 90 minutes from time zero). The reaction was then cooled to 40°C and filtered through cheesecloth. The emulsion of the polymer prepared by this method had a particle size measurement of 124 nm (by light scattering), a solids content of 39.9% (by gravimetric analysis) and residual BA and MMA monomers of 27 ppm and 98 ppm respectively (by headspace gas chromatography). Some of the latex was then freeze dried into a powder using dry ice and a vacuum oven.

[0048] Branched polymer additives #2 to #6

[0049] Branched polymer additives of different compositions were prepared using the method described above for branched polymer additive #1. Branched polymer additives #2 to #6 varied the amount of BA, the amount and composition of the CTA and the amount of crosslinker in the composition as shown in Table 2 below.

[0050] Table 2

[0051]

[0052] Polycarbonate compositions with branched polymer additives

[0053] A 26 mm laboratory co-rotating twin screw extruder equipped with a 5 mm die, L / D of 27 was used to prepare the polymer compositions containing polycarbonate resin (LEXAN EXL 2130 from Sabic), branched polymer additive #1, and MBS impact modifier (PARALOID EXL 2690 from Dow Chemical Company) under the conditions listed in Table 1. The resulting molten resin strands were cooled through a water bath. The cooled strands were cut into small pellets and the compositions were tested according to ASTM D1238 to determine their melt flow indices (MFI) as described above. The results are shown in Table 2 below. TM 141) and three different loading levels of branched polymer additive (5 wt%, 10 wt%, and 15 wt% of branched polymer additive). The resulting molten resin strands were cooled through a water bath. The cooled strands were cut into small pellets and the compositions were tested according to ASTM D1238 to determine their melt flow indices (MFI) as described above. The results are shown in Table 3 below.

[0054] Table 3

[0055]

[0056] Polycarbonate compositions with branched polymer additive and impact modifier

[0057] A 26 mm laboratory co-rotating twin screw extruder equipped with a 5 mm die, L / D of 27 was used to prepare the polymer compositions containing polycarbonate resin (LEXAN EXL 2130 from Sabic), branched polymer additive #1, and MBS impact modifier (PARALOID EXL 2690 from Dow Chemical Company) under the conditions listed in Table 1. The resulting molten resin strands were cooled through a water bath. The cooled strands were cut into small pellets and the compositions were tested according to ASTM D1238 to determine their melt flow indices (MFI) as described above. The results are shown in Table 2 below. TM 141), branched polymer additive #1, and MBS impact modifier (PARALOID EXL 2690 from Dow Chemical Company). The resulting molten resin strands were cooled through a water bath. The cooled strands were cut into small pellets which were subsequently injection molded into plaques (3.0 inch x 6.0 inch x 1 / 8 inch) which were placed in a QUV test apparatus (manufactured by Q Panel Company) for accelerated weathering testing (QUV) according to ASTM G151, ASTM G154 test standards, the exposure conditions are shown in Table 4. The plaques were measured for coloration performance after every 200 hours of QUV exposure. TM EXL 2690 from Dow Chemical Company). The resulting molten resin strands were cooled through a water bath. The cooled strands were cut into small pellets which were subsequently injection molded into plaques (3.0 inch x 6.0 inch x 1 / 8 inch) which were placed in a QUV test apparatus (manufactured by Q Panel Company) for accelerated weathering testing (QUV) according to ASTM G151, ASTM G154 test standards, the exposure conditions are shown in Table 4. The plaques were measured for coloration performance after every 200 hours of QUV exposure.

[0058] Table 4

[0059] UVA lamp 340 nm Illumination cycle: 60 °C, 8 hours Condensation cycle: 50 °C, 8 hours

[0060] Impact resistance was tested after 0 hours, 500 hours, and 1000 hours of weathering as shown in Table 5. Polymer compositions containing polycarbonate resin (LEXAN EXL 2130 from Sabic), branched polymer additive #1, and MBS impact modifier (PARALOID EXL 2690 from Dow Chemical Company) were prepared using a 26 mm laboratory co-rotating twin screw extruder equipped with a 5 mm die, L / D of 27 under the conditions listed in Table 1. The resulting molten resin strands were cooled through a water bath. The cooled strands were cut into small pellets which were subsequently injection molded into plaques (3.0 inch x 6.0 inch x 1 / 8 inch) which were placed in a QUV test apparatus (manufactured by Q Panel Company) for accelerated weathering testing (QUV) according to ASTM G151, ASTM G154 test standards, the exposure conditions are shown in Table 4. The plaques were measured for coloration performance after every 200 hours of QUV exposure. TM EXL 2690 from Dow Chemical Company). The resulting molten resin strands were cooled through a water bath. The cooled strands were cut into small pellets which were subsequently injection molded into plaques (3.0 inch x 6.0 inch x 1 / 8 inch) which were placed in a QUV test apparatus (manufactured by Q Panel Company) for accelerated weathering testing (QUV) according to ASTM G151, ASTM G154 test standards, the exposure conditions are shown in Table 4. The plaques were measured for coloration performance after every 200 hours of QUV exposure. TMThe composition (EXL2690) was prepared by processing the above composition under the conditions shown in Table 1 using a 26mm laboratory co-rotating twin-screw extruder with an L / D of 27 and equipped with a 5mm drawing die. The resulting molten resin bundle was cooled by water bath. The cooled bundle was cut into small granules, which were then injection molded into test bars for mechanical property testing. The results are shown in Tables 5 and 6 below.

[0061] Table 5

[0062]

[0063]

[0064] Table 6

[0065]

[0066]

[0067] Weatherability test

[0068] The composition was prepared and its weather resistance was tested. LEXAN was used as the base resin as described above. TM 141 polycarbonate resin and MBS impact modifier (PARALOID) TM Compositions were prepared using EXL2690. The formulations of each composition are shown in Table 7 below. Weather resistance was tested using the QUV exposure test as described above. The results of the weather resistance test are shown as a percentage of ductile fracture. Figure 1 middle.

[0069] Table 7

[0070]

[0071] Transparency of polycarbonate compositions with branched polymer additives

[0072] A polycarbonate composition comprising the branched polymer additive according to the present invention was prepared, and its light transmittance was tested. The composition was prepared as described above and has the formulation and properties shown in Table 8. Haze was measured by light transmittance using a BYK HazeGuard Plus instrument according to ASTM D1003. The results of the haze test are shown in... Figure 2 middle.

[0073] Table 8

[0074]

Claims

1. A composition comprising: (i) a resin selected from the group consisting of polycarbonates, polycarbonate-polyester blends, poly(methyl methacrylate), polyamides, poly(alkylene terephthalates), and blends thereof, the resin not comprising a multi-stage acrylic resin, and (ii) a branched polymer that is a reaction product of reactants comprising one or more monoethylenically unsaturated ester monomers, a chain transfer agent in an amount of 3 to 7 weight percent, and a crosslinking agent in an amount of 0.5 to 4 weight percent, wherein the chain transfer agent comprises butyl 3-mercaptopropionate and the crosslinking agent comprises 1,4-butanediol dimethacrylate, wherein weight percent is based on the total amount of reactants, with the proviso that the amount of crosslinking agent in moles is less than the effective amount of chain transfer agent in moles, wherein the branched polymer is not crosslinked and is soluble in the resin.

2. The composition of claim 1, wherein the one or more monoethylenically unsaturated ester monomers have the structure R’-C(O)O-R, wherein R is a hydrocarbon group of 1 to 12 carbon atoms and R’ is a monoethylenically unsaturated aliphatic group having at least 2 or 3 carbon atoms.

3. The composition of claim 1 or 2, wherein the amount of chain transfer agent is 3 to 5 weight percent.

4. The composition of claim 1 or 2, wherein the composition has a haze of 5% or less.

5. The composition of claim 1 or 2, further comprising an impact modifier.

6. The composition of claim 5, wherein the impact modifier is a methacrylate- butadiene-styrene impact modifier.

7. The composition of claim 5, comprising 1 to 10 weight percent of the impact modifier based on the total weight of the composition.

8. The composition of claim 1 or 2, comprising 50 to 99 weight percent of the resin and 1 to 50 weight percent of the branched polymer based on the total weight of the composition.

9. The composition of claim 8, comprising 75 to 95 weight percent of the resin and 5 to 25 weight percent of the branched polymer based on the total weight of the composition.

10. The composition of claim 1 or 2, wherein the resin is selected from the group consisting of polycarbonates and poly(methyl methacrylate).

11. The composition of claim 1, wherein the branched polymer is soluble in tetrahydrofuran.

12. The composition of claim 1, wherein the polymer branching ratio g’ of the branched polymer is at least 0.5 and less than 1.

13. An article comprising the composition of any of claims 1-12.

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