WO2023192401A1

WO2023192401A1 - Thermoplastic polymer composition with impact modifier

Info

Publication number: WO2023192401A1
Application number: PCT/US2023/016760
Authority: WO
Inventors: Greg ZIENTEK; Yuzhen YANG; Tetsuro Yamamoto
Original assignee: Kaneka Corporation; Kaneka Americas Holdings, Inc.
Priority date: 2022-03-30
Filing date: 2023-03-29
Publication date: 2023-10-05

Abstract

A polymer composition includes a matrix polymer and 0.1 to 30 wt% of an impact modifier including 40 to 90 wt% of an acrylate monomer, 1 to 50 wt% of at least one copolymerizable monomer, and 1 to 30 wt% of a functional monomer. A method includes blending a matrix polymer with 0.1 to 30 wt% of an impact modifier to produce a polymer composition.

Description

THERMOPLASTIC POLYMER COMPOSITION WITH IMPACT MODIFIER

BACKGROUND

[0001] Thermoset resins (“thermosets”) and thermoplastic resins (“thermoplastics”) are distinct classes of polymers, distinguished from each other based on their behavior in the presence of heat. Specifically, thermoplastics such as polyethylene (PE), polycarbonate (PC), and polyetheretherketone (PEEK) become pliable or moldable upon application of heat (solidifying upon cooling), whereas thermosets such as epoxy, benzoxazine, and bismaleimide are irreversibly hardened upon curing, and cannot be melted or reshaped on heating. Thus, thermoplastic materials have melt temperatures (a melting point) where they start to flow, while thermoset products that have been cured can withstand higher temperatures without loss of their structural integrity. Both thermosets and thermoplastics have been used in advanced composites as components for applications such as aerospace structures and interior components.

[0002] Thermoplastic resins provide benefits such as not requiring crosslinking (curing), an indefinite shelf life at room temperature (in the absence of UV irradiation), short molding time, improved fire/smoke/toxicity (FST) performance, remoldability, enhanced vibration damping and acoustic attenuation, superior impact damage tolerance (impact toughness), an ability to tailor material forms (design flexibility), superior shear and fracture strength, and recyclability. Thermoplastics also offer the option to fuse or weld molded subcomponents, which can reduce assembly weight and stress concentrations by eliminating fasteners and adhesives.

[0003] Many thermoplastics employ impact modifiers to improve mechanical properties such as toughness. However, conventional impact modifiers to improve toughness may adversely affect other properties necessary for processability, such as melt properties. Accordingly, there exists a need for impact modifiers that improve the toughness of thermoplastics while maintaining good properties related to processability. SUMMARY

[0004] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0005] In one aspect, embodiments disclosed herein relate to a polymer composition including a matrix polymer and 0.1 to 30 wt% of an impact modifier. The impact modifier may include 40 to 90 wt% of an acrylate monomer, 1 to 50 wt% of at least one copolymerizable monomer, and 1 to 30 wt% of a functional monomer.

[0006] In another aspect, embodiments disclosed herein relate to a method including blending a matrix polymer with 0.1 to 30 wt% of an impact modifier to produce a polymer composition. The impact modifier may include 40 to 90 wt% of an acrylate monomer, 1 to 50 wt% of at least one copolymerizable monomer, and 1 to 30 wt% of a functional monomer.

[0007] Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.

DETAILED DESCRIPTION

[0008] Impact modifiers may be added to polymer compositions to improve properties such as impact resistance, heat stability, and processability. Often, a given impact modifier will enhance one property while sacrificing another. For example, impact modifiers that are used to improve the toughness of thermoplastic resins often include crosslinkers. Due to the presence of a crosslinker, such impact modifiers result in decreased processability of the thermoplastic resin. Thus, impact modifiers that can improve the toughness of thermoplastic resins and do not contain a crosslinker may provide polymer compositions exhibiting good impact strength and processability.

[0009] Accordingly, embodiments of the present disclosure generally relate to polymer compositions comprising an impact modifier that does not include a crosslinker. The impact modifier may improve the properties of polymer compositions, including the toughness and tensile elongation, while maintaining or enhancing the melt flow rate, thus providing a polymer with good processability. As such, impact modifiers of one or more embodiments may be particularly useful in thermoplastic polymer compositions. Impact modifiers of the present disclosure may be prepared by polymerization of an acrylate monomer, at least one copolymerizable monomer, and a functional monomer.

[0010] Polymer Composition

[0011] In one aspect, embodiments disclosed herein relate to a polymer composition comprising a matrix polymer and an impact modifier. As previously described, polymer compositions including an impact modifier may exhibit improved impact properties, and thus, may be useful in various industries.

[0012] The matrix polymer of one or more embodiments may be a thermoplastic polymer. In the present disclosure, a thermoplastic polymer refers to a polymer that has a crystalline structure that may soften when heated and harden when cooled. Any type of thermoplastic polymer may be suitable in the disclosed polymer compositions. For example, in one or more embodiments, the matrix polymer may be polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate alloys (such as, but not limited to, PC/PBT, PC/PET, and PC/acetonitrile butadiene styrene (ABS)), polyamides (PA) (such as, but not limited to, nylon 6, nylon 66, nylon 11, nylon 12, nylon 6/66, nylon 66/6T, nylon 6T/6I, and mixtures thereof), polyesters, polyethers, polysulfides, and combinations thereof, among others.

[0013] In one or more embodiments, the matrix polymer may have a weight average molecular weight ranging from about 5,000 to 200,000 Da (Dalton). For example, matrix polymers may have a weight average molecular weight having a lower limit of any of 5,000, , 10,000 and 20,000, 30,000, 40,000, 50,000 and 70,000 Da and an upper limit of any of 80,000, 100,000, 120,000, 140,000, 160,000, 180,000, 200,000 Da, where any lower limit may be paired with any mathematically compatible upper limit.

[0014] In one or more embodiments, the polymer composition may comprise a matrix polymer in an amount of about 50 to 99.9 wt% (weight percent) based on the total weight of the polymer composition. For example, the amount of matrix polymer included in polymer composition may range from a lower limit of any of 50, 55, 60, 65, 70, 75, and 80 wt% to an upper limit of any of 70, 75, 80, 85, 90, 95, 96, 97, 98, 99, 99.5, and 99.9 wt%, where any lower limit may be paired with any mathematically compatible upper limit.

[0015] As described above, polymer compositions of the present disclosure include an impact modifier. The impact modifier may comprise an acrylate monomer, at least one copolymerizable monomer, and a functional monomer. Notably, the impact modifier does not include a crosslinker. Conventional impact modifiers contain crosslinkers such as butadiene, divinyl benzene, 1,4-butanediol, dimethacrylate and allylmethacrylate, so as to maintain a discrete shape and suitable dispersion within a matrix polymer, in order to enhance the toughness or the polymer. In contrast, the present impact modifier may provide polymers with increased toughness without the inclusion of a crosslinker.

[0016] In one or more embodiments, the impact modifier includes an acrylate monomer. Suitable examples of the acrylate monomer include alkyl acrylates containing an alkyl group having 1 to 8 carbon atoms such as 2-ethyl hexyl acrylate, butyl acrylate, ethyl acrylate and methyl acrylate; methacrylates having an alkyl group with 1 to 22 carbon atoms, such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, dodecyl methacrylate, stearyl methacrylate, and behenyl methacrylate; and acrylates having an alkyl group with 1 to 22 carbon atoms and an alkoxy group. These acrylate monomers can be used alone or in combination. The number of carbon atoms of the alkyl group in the acrylate is not necessarily limited, but, for example, if the number of carbon atoms is more than 22, the polymerizability may be deteriorated, and thus acrylates having an alkyl group with 22 or fewer carbon atoms may result in better polymerization. Acrylates having an alkyl group with 3 to 8 carbon atoms may be particularly useful because they have excellent compatibility with a thermoplastic resin. In one or more particular embodiments, the acrylate monomer may be butyl acrylate.

[0017] The impact modifier in accordance with one or more embodiments may include an acrylate monomer in an amount ranging from 40 to 90 wt% based on the total amount of the impact modifier. For example, an acrylate monomer may be present in the impact modifier of one or more embodiments in an amount having a lower limit of any of 40, 45, 50, 55, 60, 65, 70, and 75 wt% and an upper limit of any of 60, 65, 70, 75, 80, 85, and 90 wt%, where any lower limit may be paired with any mathematically compatible upper limit.

[0018] In one or more embodiments, the impact modifier includes at least one copolymerizable monomer. The copolymerizable monomer may be any monomer that is capable of co-reacting with the previously described acrylate monomer. Suitable copolymeriable monomers include, but are not limited to, (meth)acrylates having an alkyl group with 1 to 22 carbon atoms, such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, dodecyl methacrylate, and stearyl methacrylate, styrene, alpha methyl styrene, acrylonitrile, and combinations thereof. In particular embodiments, the copolymerizable monomer is methyl methacrylate or n-butyl methacrylate.

[0019] The copolymerizable monomer may be included in the impact modifier in an amount ranging from 1 to 50 wt%, based on the total amount of impact modifier. For example, impact modifier disclosed herein may comprise an amount of copolymerizable monomer having a lower limit of any of 1, 2, 5, 10, 15, 20, 25, 30, and 35 wt% and an upper limit of any of 25, 30, 35, 40, 45, 48, and 50 wt%, where any lower limit may be paired with any mathematically compatible upper limit. In particular embodiments, the copolymerizable may be included in a range of 15 to 35 wt% based on the total amount of the impact modifier.

[0020] In one or more embodiments, the impact modifier includes a functional monomer. As used herein, a “functional monomer” is a monomer that contains at least two reactive functional groups, one that may react with the other monomers to produce the impact modifier, and one that remains unreacted. Such functional groups may react with the matrix polymer in embodiment compositions.

[0021] Functional monomers may include reactive functional groups such as epoxy groups, carboxyl groups, isocyanate groups, acid anhydride groups, aziridine groups, urethane groups, and acyl chloride groups. Suitable examples of functional monomers include, but are not limited to, glycidyl methacrylate (GMA), (meth)acrylic acid (MAA), glycidyl acrylate (GA), maleic anhydride (MAH), tert-butyl methacrylate (t- BuMA), and combinations thereof. [0022] Impact modifiers may include a functional monomer in an amount ranging from 1 to 30 wt% based on the total amount of impact modifier. For example, in one or more embodiments, functional monomers may be present in impact modifiers in an amount range having a lower limit of any of 1, 2, 5, 7, 9, 10, 12, and 15 wt% and an upper limit of any of 12, 15, 18, 20, 22, 25, 28, and 30 wt%, where any lower limit may be paired with any mathematically compatible upper limit.

[0023] In one or more embodiments, the polymer composition may comprise the impact modifier in an amount of about 0.1 to 30 wt%. For example, the impact modifier may be included in polymer compositions in an amount having a lower limit of any of 0.1, 0.5, 1.0, 2.0, 5.0, 8.0, and 10 wt% and an upper limit of any of 10, 15, 20, 22, 25, 27, and 30 wt% where any lower limit may be paired with any mathematically compatible upper limit. In particular embodiments, the impact modifier may be present in the polymer composition in an amount ranging from 5.0 to 10 wt%.

[0024] In one or more embodiments, the impact modifier may have a weight average molecular weight ranging from about 100,000 to 4,000,000 g/mol. For example, the weight average molecular weight of impact modifiers may have a range having a lower limit of any of 100,000, 150,000, 200,000, 250,000, 300,000, 400,000, and 500,000 Da and an upper limit of any of 500,000, 1,000,000, 2,000,000, 2,500,000 3,000,000, 3,500,000, and 4,000,000 Da, where any lower limit may be paired with any mathematically compatible upper limit.

[0025] In one or more embodiments, the polymer composition may also include conventionally known additives, for example, antioxidants; anti-dripping agents; polymer impact modifiers; flame retardants; impact modifiers; melt flow-improving agents; plasticizers; lubricants; ultraviolet absorbers; ultraviolet stabilizers, thermal stabilizers, colorants, pigments, dyes; fiber reinforcing agents; glass fibers; glass beads; glass flakes; inorganic fillers, such as talc, mica, kaolin, clay, calcium carbonate, oxides of titanium, zinc oxide nanoparticles, layer silicate, metallic microparticles, and carbon nanotubes; polymer lubricants; and mold-release agents. Such additives may be included in an amount ranging from 0.1 to 1.0 phr. For example, the additive may be present in an amount having a lower limit of any of 0.1, 0.2 and 0.3 phr and an upper limit of any of 0.8, 0.9 and 1.0 phr, where any lower limit may be paired with any mathematically compatible upper limit.

[0026] In particular embodiments, fillers, such as, but not limited to, glass fibers, may be incorporated into the polymer composition in an amount ranging from 10 to 50 wt%, based on the weight of the total composition. For example, in one or more embodiments, the polymer composition may include glass fibers in an amount having a lower limit of any of 10, 15, 20, 25, and 30 wt%, and an upper limit of any of 25, 30, 35, 40, 45, and 50 wt%, where any lower limit may be paired with any mathematically compatible upper limit.

[0027] In one or more embodiments, polymer articles may be prepared from the polymer composition disclosed herein. The types of polymer articles that may be produced from the polymer composition are not particularly limited. For example, polymer articles may be extruded profiles, co-extruded profiles, injection molded articles, compression molded articles, film extruded articles, metal insert molded articles, rotational molded articles, and blow molded articles.

[0028] Polymer Properties

[0029] As previously described, the disclosed impact modifier may include unreacted functional groups at the ends of the polymer chains due to the inclusion of the functional monomer in the impact modifier that may be referred to herein as “reactive end groups”. The reactive end groups may form covalent bonds with the matrix polymer of embodiment compositions. As such, impact modifiers including reactive end groups may provide polymer compositions that exhibit improved impact properties due to the crosslinking between the reactive end groups and the matrix polymer. In particular, properties such as the toughness and maximum tensile elongation may be sufficiently improved without adversely affecting other properties, such as the melt strength, in polymer compositions including disclosed impact modifiers.

[0030] In one or more embodiments, polymer compositions may have improved toughness as compared to a polymer composition without the impact modifier described herein. The toughness of a polymer composition may be described as its ability to resist fracturing and/or deformation when force is applied. Compositions with high toughness may exhibit both good strength and ductility. Impact tests measure the ability of a material to absorb energy during deformation and may be performed to determine the toughness of a given polymer composition. The results of an impact test may be expressed as the amount of energy absorbed (kJ) per unit cross sectional area (m²).

[0031] Polymer compositions including the presently described impact modifier may have improved toughness as compared to polymer compositions including similar commercially available impact modifiers. While the addition of impact modifiers to polymer compositions may improve the toughness, it can often adversely affect other polymer properties. For example, the melt strength may be reduced in polymer compositions containing impact modifiers that are known in the art. Alternatively, embodiment polymer compositions that include disclosed impact modifiers may exhibit improved toughness while maintaining or enhancing melt strength.

[0032] One or more embodiment polymer compositions may exhibit maximum tensile elongation similar to polymer compositions without the impact modifier described herein. Similar to melt strength, the addition of impact modifiers to polymer compositions commonly decreases the maximum tensile elongation. The maximum tensile elongation of polymer compositions that comprise the disclosed impact modifier may be sufficiently greater than that of polymer compositions that comprise similar commercially available impact modifiers.

[0033] Polymer Preparation

[0034] In another aspect, embodiments disclosed herein relate to a method of preparing the previously described polymer composition comprising a matrix polymer and an impact modifier.

[0035] In one or more embodiments, an impact modifier as previously described is prepared first. A method for preparing the impact modifier may include synthesizing a copolymer of the previously described acrylate monomer and functional monomer, and then polymerizing the copolymer with a copolymerizable monomer to form the impact modifier. [0036] The copolymer of the acrylate monomer and functional monomer may be prepared via emulsion polymerization. The emulsion polymerization may be carried out in an aqueous solution. The aqueous solution includes water. The water may be purified water such as distilled water or deionized water. The aqueous solution may include an emulsifier and at least one redox catalyst. Suitable redox catalysts include, but are not limited to, ethylenediaminetetraacetic acid (EDTA), ferrous sulfate, sodium formaldehydesulfoxylate, and combinations thereof. The emulsifier may be sodium ethoxylated alkyl phosphate ester. The emulsifier and at least one redox catalyst may be included in the aqueous solution in a combined amount ranging from 0.05 wt% to 1.0 wt% based on the total weight of the aqueous solution. In particular embodiments, the aqueous solution includes an emulsifier and at least on redox catalyst in a combined amount of 0.35 wt%.

[0037] The aqueous solution may be degassed with nitrogen or argon for approximately 30 minutes, before adding a first monomer mixture. During degassing, the aqueous solution may be stirred and heated to an elevated temperature. The elevated temperature may be sufficient for polymerization of the first monomer mixture to occur, once added. For example, nitrogen may be bubbled through the aqueous solution at a temperature of 50 to 100 °C for 30 minutes, to effectively degas the solution.

[0038] The method may then include slow addition of a first monomer mixture into the aqueous solution. The first monomer mixture may include an acrylate monomer and a functional monomer as previously described. The first monomer mixture may optionally include a radical initiator such as /c/7-buty I hydroperoxide, di- tert-butyl peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, AIBN and ABCN, among others. Such radical initiator may be present in the first monomer mixture in an amount of 0.001 to 0.05 wt%, based on the total weight of the acrylate and functional monomers.

[0039] As detailed above, the first monomer mixture may be added to the aqueous solution by slow addition. Reaction of the first monomer mixture with the aqueous solution may be an exothermic reaction. As such, slow addition of the first monomer mixture may limit the temperature increase that may occur in an exothermic reaction. For example, the first monomer mixture may be added dropwise or in other small increments relative to the total volume of first monomer mixture. After slow addition of the first monomer mixture, an additional amount of the radical initiator may be added. Then, the mixture may be stirred at the elevated temperature for a time sufficient to achieve at least 90% conversion to a copolymer of the acrylate monomer and the functional monomer. Conversion may be measured by obtaining a first weight of the mixture, then inhibiting polymerization by adding a polymer inhibitor to the mixture, curing the mixture, and obtaining a second weight of the mixture, now a cured polymer. Using the first weight, the second weight, and a theoretical solid content, % conversion may be calculated. After achieving 90% conversion, the mixture may be stirred at the elevated temperature for an additional amount of time.

[0040] The copolymer of the acrylate and functional monomers may behave like an elastomer. Elastomers are polymers having elastic properties and are known to those in the art as “soft” polymers. Thus, the copolymer may have a glass transition temperature (Tg) much lower than the desired product impact modifier. For example, whereas the desired impact modifier may have a Tg of about 105 °C, for example, the copolymer of acrylate and functional monomers may have a Tg ranging from 35 to 50 °C. Accordingly, although the functional monomer is a reactive component, in order to include the disclosed impact modifier in a thermoplastic polymer resin, the copolymer is further polymerized with the copolymerizable monomer such that a coating is formed over the elastomeric copolymer and a hard impact modifier is formed. Coating the elastomer with the copolymerizable monomer provides an impact modifier that may be made into a pure, dry powder, rather than larger pieces of polymer that are difficult to dehydrate and dry.

[0041] As such, after the additional amount of time stirring, a second monomer mixture may be added slowly to the copolymer of acrylate and functional monomers. In one or more embodiments, the second monomer mixture includes the previously described copolymerizable monomer. The second monomer mixture may optionally include a radical initiator and/or a chain transfer agent in an amount ranging from 0.001 to 0.05 wt% based on the weight of the copolymerizable monomer. Suitable radical initiators include ZerZ-butylhydroperoxide, di-ZerZ-butyl peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, AIBN and ABCN, among others. Suitable chain transfer agents include, but are not limited to, pentaphenyl ethane, carbon tetrabromide, tert-dodecyl mercaptan, 4-methylbenzenethiol, tert-nonyl mercaptan, isooctyl 3- mercaptopropionate, and bromo trichloromethane. The second monomer mixture may be added to the copolymer of acrylate and functional monomers over an amount of time ranging from 30 to 60 minutes. After slow addition of the second monomer mixture, the reaction may be stirred at the elevated temperature for a time sufficient to achieve 98% conversion to the crude impact modifier.

[0042] In one or more embodiments, the method may include purifying the crude impact modifier such that a powder is formed. The crude impact modifier may be added to a brine at a temperature below ambient with agitation. The brine may be an aqueous solution including a salt such as NaCl, Ca(CH3COO)2, MgSC , MgCh, HC1, H2SO4, or CaCh. Agitation of the crude copolymer material may provide a powder- like precipitate in the brine. The temperature may then be increased. Subsequently, the precipitate may be separated from the brine via decanting or filtration, for example, and then dried at an elevated temperature to yield a pure impact modifier.

[0043] In one or more embodiments, the method may then include mixing a matrix polymer and the prepared impact modifier to produce a polymer composition, where the matrix polymer and the impact modifier may have structures, compositions, and properties as described in the previous sections. The matrix polymer and the impact modifier may be mixed at an elevated temperature. Any elevated temperature may be used, provided that it is sufficient to melt the matrix polymer and the impact modifier. At a sufficient elevated temperature, the impact modifier may melt, providing access to the functional monomer that is otherwise “coated” in the copolymerizable monomer.

[0044] The matrix polymer and impact modifier may be mixed by any suitable mixing method. In one or more embodiments, conventional processes including extrusion, co-extrusion, high-shear mixing, and the like may be used. Equipment including a single- screw extruder, twin-screw extruder, banbury mixer, or heating roller may be suitable for mixing the matrix polymer and the impact modifier. The matrix polymer and the impact modifier may be mixed by dissolving the components in a solvent. [0045] In one or more embodiments, the mixing may be conducted at a temperature ranging from a lower limit selected from any one of 50, 60, 70, 80, 90, 100 and 120 °C to an upper limit selected from any one of 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, and 300 °C, where any lower limit may be paired with any upper limit. As noted above, the mixing temperature may be selected based on the melting points of the matrix polymer and the impact modifier.

[0046] The matrix polymer and the impact modifier may be mixed for a time suitable for the polymerization reaction to be complete. The reaction time may be typically at least one minute.

[0047] In one or more embodiments, the method may further include forming a polymer article from the polymer composition. Forming the article may be performed by any conventional processes including extrusion, co-extrusion, injection molding, compression molding, film extrusion, blow molding, foam extrusion, metal insert molding, rotational molding, calendaring, fiber spinning, and the like. In one or more particular embodiments, the forming may be performed by extrusion, co-extrusion, injection molding, compression molding, film extrusion, and blow molding.

[0048] In some embodiments, the mixing process and the forming process may be conducted using a single process. For example, an extruder containing a die may be used to mix the matrix polymer and the impact modifier, and an article, such as a sheet or a rod, may be extruded through the die of the extruder.

[0049] In other embodiments, the mixing process and the forming process may be conducted separately using the same or different processes. For example, an extruder may be used to mix the matrix polymer and the impact modifier to produce a polymer composition in an intermediate form such as pellets, flakes, and powders. The polymer composition in the intermediate form may be processed further by a process such as injection molding, extruder, blow molder, or film extrusion to produce a polymer article.

[0050] The process of forming a polymer article may include using a polymer article as an intermediate article and further forming the intermediate article to produce a final polymer article that is different from the intermediate article. For example, a sheet or rod may be formed from the polymer composition as an intermediate article, and subsequently turned into a final article by a process such as compression molding.

[0051 ] Examples

[0052] The following examples are provided to illustrate embodiments of the present disclosure. The examples are not intended to limit the scope of the present invention, and they should not be so interpreted.

[0053] Impact Modifier 1

[0054] Impact Modifier 1 was prepared according to the following procedure. A reaction flask was charged with 220 phr (parts per hundred resin) purified water, 0.05 phr sodium ethoxylated alkyl phosphate ester (made from RD910Y supplied by Toho Chemical and sodium hydroxide by Wako Chemical), 0.0032 phr EDTA (ethylenediaminetetraacetic acid) supplied by Wako Chemical, 0.0008 phr ferrous sulfate 7-hydrate supplied by Wako Chemical, and 0.721 phr sodium formaldehydesulfoxylate. The resulting mixture was stirred at 68 °C under N2 bubbling for 30 minutes. A first monomer mixture including 60 phr butyl acrylate (BA) supplied by Mitsubishi Chemical, 5 phr glycidyl methacrylate (GMA) supplied by Nippon Shokubai, and 0.08 phr t-Butylhydroperoxide supplied by Nichiyu was added dropwise to the mixture over 255 minutes. After addition of the first monomer mixture, 0.08 phr sodium ethoxylated alkyl phosphate ester and 0.52 phr t- Butylhydroperoxide were added to the mixture. The mixture was allowed to stir at 68 °C until 90% conversion to the BA/GMA copolymer was achieved. Conversion was measured according to the following procedure. The weight of a metal can was obtained and recorded. A portion of the copolymer was placed on the metal can, and a first weight was measured. Then, 2 drops of 1% H-tempo aqueous solution were added to the portion of the copolymer to inhibit polymerization. The copolymer was dried at 120 °C for 30 minutes and then cooled to room temperature, at which point a second weight was measured. The conversion was calculated according to the following equation: (first weight - weight of metal can)/(second weight - weight of metal can)/( theoretical solid content). Once 90% conversion was achieved, the mixture was maintained at 68 °C for an additional 30 minutes. [0055] After 30 minutes, a second monomer mixture including 35 phr methyl methacrylate (MMA) supplied by Nippon Shokubi and 0.2 phr t-Butylhydroperozide was added dropwise to the reaction mixture over 45 minutes. Then, 0.026 phr t- Butylhydroperoxide was added to the reaction, and the mixture was allowed to stir at 68 °C until conversion of over 98% to the BA/GMA/MMA copolymer was achieved.

[0056] Resulting Impact Modifier 1 particles had a volume average particle size (PS), as measured by nanotrack Primix, of 1431 A, a weight average molecular weight (Mw) of about 150,000 g/mol and a number average molecular weight (Mn) of about 44,000 g/mol. The glass transition temperature (Tg) of Impact Modifier 1 was 105 °C.

[0057] The BA/GMA/MMA copolymer was obtained by coagulation as follows: the crude copolymer was added into a 5% solution of calcium chloride (CaCh) supplied by Wako Chemical in water at 10 °C with agitation. Agitation of the crude copolymer material provided a powder-like precipitate in the aqueous CaCh solution. The temperature was then increased to 85 °C. Then, the aqueous phase was decanted from the precipitate and the precipitate was dried at 50 °C to yield pure Impact Modifier 1.

[0058] Impact Modifier 2

[0059] Impact Modifier 2 was prepared according to the method described above for Impact Modifier 1, using a first monomer mixture including 60 phr butyl acrylate, 10 phr glycidyl methacrylate, and 0.08 phr t-Butylhydroperoxide, and a second monomer mixture including 30 phr methyl methacrylate and 0.2 phr t-Butylhydroperozide. The resulting Impact Modifier 2 had a PS of 1500 A, a Tg of 105 °C, a Mw of about 142,000 g/mol and a Mn of about 33,000 g/mol.

[0060] Impact Modifier 3

[0061] Impact Modifier 3 was prepared according to the method described above for Impact Modifier 1, using a first monomer mixture including 60 phr butyl acrylate, 10 phr glycidyl methacrylate, and 0.085 phr t-Butylhydroperoxide, and a second monomer mixture including 30 phr methyl methacrylate and 0.03 phr t- Butylhydroperozide. Resulting Impact Modifier 3 had a PS of 2078 A, a Tg of 105 °C and a Mw of about 266,000 g/mol.

[0062] Impact Modifier 4 [0063] Impact Modifier 4 was prepared according to the method described above for Impact Modifier 1, using a first monomer mixture including 70 phr butyl acrylate, 5 phr glycidyl methacrylate, and 0.08 phr t-Butylhydroperoxide, and a second monomer mixture including 25 phr methyl methacrylate and 0.2 phr t-Butylhydroperozide. Resulting Impact Modifier 4 had a PS of 1503 A, a Tg of 105 °C, a Mw of about 142,000 g/mol and a Mn of about 37,000 g/mol.

[0064] Impact Modifier 5

[0065] Impact Modifier 5 was prepared according to the method described above for Impact Modifier 1, using a first monomer mixture including 80 phr butyl acrylate, 5 phr glycidyl methacrylate, and 0.085 phr t-Butylhydroperoxide, and a second monomer mixture including 15 phr methyl methacrylate and 0.015 phr t- Butylhydroperozide. Resulting Impact Modifier 5 had a PS of 1700 A, a Tg of 105 °C, a Mw of about 266,000 g/mol and a Mn of about 93,000 g/mol.

[0066] Impact Modifier 6

[0067] Impact Modifier 6 was prepared according to the method described above for Impact Modifier 1, using a first monomer mixture including 80 phr butyl acrylate, 5 phr glycidyl methacrylate, and 0.085 phr t-Butylhydroperoxide, and a second monomer mixture including 15 phr methyl methacrylate and 0.03 phr t-dodecyl mercaptan. Resulting Impact Modifier 6 had a PS of 2321 A, a Tg of 105 °C, a Mw of about 255,000 g/mol and a Mn of about 67,000 g/mol.

[0068] Impact Modifier 7

[0069] Impact Modifier 7 was prepared according to the method described above for Impact Modifier 1, using a first monomer mixture including 75 phr butyl acrylate, 5 phr glycidyl methacrylate, and 0.08 phr t-Butylhydroperoxide, and a second monomer mixture including 20 phr methyl methacrylate, 0.02 phr t-Butylhydroperozide, and 0.04 phr t-dodecyl mercaptan. Resulting Impact Modifier 7 had a PS of 1333 A, a Tg of 105 °C, a Mw of about 184,000 g/mol and a Mn of about 60,000 g/mol.

[0070] Impact modifier 8 is a commercially available impact modifier comprising ethyl acrylate monomer, methacrylate monomer, and glycidyl methacrylate monomer. Impact modifier 9 is a silicon-based commercially available impact modifier provided by Kaneka Corp. Impact modifier 10 is an aery lie -based commercially available impact modifier provided by Kaneka Corp.

[0071 ] Examples 1-15

[0072] Inventive compositions were prepared using Duranex 300FP and 500FP, commercially available PBT polymers supplied by Polyplastics, glass fiber T187H supplied by NEG Co. Etd. and varying amounts of one of Impact Modifiers 1-7. The intrinsic viscosities of the Duranex PBT polymers were 0.5 and 0.75 dE/g, respectively. The PBT polymer and one of Impact Modifiers 1-7 were mixed together by hand dry blending to provide inventive compositions. Additives IrganoxlOlO and Irgafosl68S, supplied by BASF, were added at an amount of 0.1 phr for all examples.

[0073] Comparative Examples 1-10

[0074] Comparative compositions were prepared using Duranex 300FP and 500FP, commercially available PBT polymers supplied by Polyplastics and varying amounts of one of Impact Modifiers 8 and 9. The intrinsic viscosities of the Duranex PBT polymers were 0.5 and 0.75 dL/g, respectively. The PBT polymer and one of Impact Modifiers 8 and 9 were mixed together by hand dry blending to provide comparative compositions. The compositions of the inventive and comparative and inventive examples are shown in Table 1. Additives IrganoxlOlO and Irgafosl68S, supplied by BASF, were added at an amount of 0.1 phr for all comparative examples.

[0075] Table 1. Compositions of inventive and comparative examples in wt%.

[0076] The properties of the inventive and comparative example polymers are shown in Tables 2 and 3. Table 2. Properties of inventive polymer compositions.

Table 3. Properties of comparative polymer compositions

[0077] The properties of Examples 1-15 and Comparative Examples 1-10 as shown in Tables 2 and 3 were evaluated and are discussed below. The IZOD, tensile strength, MFR, and Flex modulus were all measured according to the standards JIS K7110, JIS K7162, JIS K7210, and JIS K7171, respectively.

[0078] A maximum tensile elongation refers to the ratio of difference between the final length of the specimen (or the length of the specimen under tensile force at break) and the initial length of the specimen, on the one hand, and the initial length of the specimen, on the other hand. The maximum tensile elongation may be determined by the following formula: 100

where Lf is the final length of the specimen, and Li is the initial length of the specimen.

[0079] The polymer compositions of Examples 1-9 and Comparative Examples 1-5 were formed into a tensile test specimen, and a tensile test was conducted at a test temperature of 23 °C and a test speed of 50 mm/min. As shown in Tables 2 and 3, the maximum tensile elongation of Example 5 is similar to the maximum tensile strength of PBT (Comparative Example 1). Example 5, which contains the impact modifier at a loading of 5 wt%, has significantly higher maximum tensile elongation than Comparative Examples 2 and 3, which contain impact modifier 8 and 9, respectively, at the same loading.

[0080] As previously described, polymer compositions may have improved toughness as compared to polymer compositions without an impact modifier (e.g., Comparative Example 1) as well as polymer compositions comprising a commercially available impact modifier e.g., Comparative Examples 2-5). Impact tests measure the ability of a material to absorb energy during deformation and may be performed to determine the toughness of a given polymer composition. The results of an impact test may be expressed as the amount of energy absorbed (kJ) per unit cross sectional area (m²).

[0081] The IZOD impact strength at 23 °C of all exemplary polymer compositions (Examples 1-11) was greater than that of the PBT without an impact modifier (Comparative Example 1), as shown in Tables 2 and 3. At 5 wt% loading, Example 5 had greater toughness than Comparative Examples 2 and 3. Specifically, the toughness of Example 5 was 7.2 kJ/m², whereas the toughness of Comparative Example 2 and Comparative Example 3 was 6.5 kJ/m² and 6.8 kJ/m², respectively. At 10 wt% the toughness of Example 9 (12.3 kJ/m²) was comparable to that of Comparative Example 4 (12.6 kJ/m²) and sufficiently greater than that of Comparative Example 5 (8.3 kJ/m²).

[0082] The IZOD impact strength at -30 °C of all example polymer compositions (Examples 1-11) was greater than that of the PBT without an impact modifier (Comparative Example 1), as shown in Tables 2 and 3. In particular, the toughness of Example 5 (4.6 kJ/m²) was greater than the toughness of Comparative Example 2 (4.4 kJ/m²), which contained closely related impact modifier 1. Similarly, at a higher loading of 10 wt%, Example 9 (5.9 kJ/m²) had a slightly greater toughness than Comparative Example 4 (5.8 kJ/m²).

[0083] As disclosed above, the polymer compositions may comprise reinforcing fillers. The IZOD impact strength at 23 °C of all inventive PBT/glass fiber compositions (examples 12-15) was greater than the IZOD strength of the polymer compositions of Comparatives Examples 6-10. Even higher IZOD impact strengths are seen at -30°C for the inventive examples including the PBT/glass fiber formulation with impact modifier 1 and 3 compared to that of Comparatives Examples comprising acrylic impact modifiers. Similarly, at a higher loading of 10 wt% of impact modifier 1, example 15 had a greater toughness than Comparative Example 10 at both at 23 °C and -30°C.

[0084] As disclosed above, impact modifiers that have been incorporated into a polymer composition often decrease the melt strength of that polymer. Melt strength as an important property for determining the processability of a given polymer. Thus, it is unfavorable to reduce the melt strength of any polymer that may be further processed and used in various industries. The melt strength may be measured by the melt flow rate of a given polymer composition. The MFR was measured at 250 °C with 2.16 kg sample.

[0085] As shown in Tables 2 and 3, the melt flow rate of all Examples including 5 wt% impact modifier (1-5) was greater than the melt flow rate of the polymer compositions of Comparative Example 2. Similarly, the melt flow rate of Examples 6-11 (having 10 wt% loading of impact modifier) was significantly greater than the same of Comparative Example 4. Further, the melt flow rate of Examples 6 and 9-11 was also greater than that of Comparative Example 5.

[0086] When the measured properties are combined, it can be seen that the exemplary polymer compositions exhibit increased toughness and melt strength at both impact modifier loadings. Conversely, Comparative Examples 2 and 4 may have improved toughness due to the presence of impact modifier 8, however, the melt strength is clearly reduced. Likewise, the melt strength of Comparative Examples 3 and 5 is high, whereas the toughness is reduced. The impact modifier of the present disclosure may significantly increase the toughness of a given polymer composition without adversely affecting the melt strength. As such, there are clear advantages to polymer compositions according to one or more embodiments of the present disclosure.

[0087] Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112(f) for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.

Claims

CLAIMS What is claimed:

1. A polymer composition comprising: a matrix polymer; and

0.1 to 30 wt% of an impact modifier comprising:

40 to 90 wt% of an acrylate monomer;

1 to 50 wt% of at least one copolymerizable monomer; and

1 to 30 wt% of a functional monomer.

2. The polymer composition of claim 1, wherein the impact modifier does not include a crosslinker.

3. The polymer composition of claim 1 or 2, wherein the acrylate monomer is butyl acrylate.

4. The polymer composition of any preceding claim, wherein the at least one copolymerizable monomer is selected from the group consisting of (meth)acrylates, methyl methacrylate, butyl methacrylate, styrene, alpha methyl styrene, acrylonitrile, and combinations thereof.

5. The polymer composition of any preceding claim, wherein the at least one copolymerizable monomer is methyl methacrylate.

6. The polymer composition of any preceding claim, wherein the functional monomer comprises an epoxy functional group.

7. The polymer composition of any preceding claim, wherein the functional monomer is glycidyl methacrylate.

8. The polymer composition of any preceding claim, wherein the functional monomer is present in the impact modifier as functional end groups.

9. The polymer composition of any preceding claim, wherein the impact modifier has a weight average molecular weight range from 100,000 g/mol to 4,000,000 g/mol. The polymer composition of any preceding claim, wherein the matrix polymer is a thermoplastic polymer. The polymer composition of claim 10, wherein the thermoplastic polymer is a polymer selected from the group consisting of polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polycarbonate (PC), PC/PBT, PC/PET, PC/acetonitrile butadiene styrene (ABS), nylon 6, nylon 66, nylon 11, nylon 12, nylon 6/66, nylon 66/6T, nylon 6T/6I, polyesters, polyethers, polysulfides, and combinations thereof. The polymer composition of any preceding claim, wherein the matrix polymer comprises an inorganic filler selected from the group consisting of glass fibers, glass beads, glass flakes, talc, mica, kaolin, clay, and combinations thereof. The polymer composition of any preceding claim, wherein the matrix polymer comprises an additive selected from the group consisting of flame retardants, antioxidants, thermal stabilizers, ultraviolet absorbers, ultraviolet stabilizers, lubricants, mold-release agents, impact modifiers, colorants, pigments, dyes, and combinations thereof. The polymer composition of any preceding claim, wherein the polymer composition has a melt flow rate of at least 2 g/min. A polymer article comprising the polymer composition of any of the above claims. A method comprising: blending a matrix polymer with 0.1 to 30 wt% of an impact modifier to produce a polymer composition, wherein the impact modifier comprises:

40 to 90 wt% of an acrylate monomer;

1 to 50 wt% of at least one copolymerizable monomer; and

1 to 30 wt% of a functional monomer. The method of claim 16, wherein the matrix polymer is a thermoplastic polymer selected from the group consisting of polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polycarbonate (PC), PC/PBT, PC/PET, PC/acetonitrile butadiene styrene (ABS), nylon 6, nylon 66, nylon 11, nylon 12, nylon 6/66, nylon 66/6T, nylon 6T/6I, polyesters, polyethers, polysulfides, and combinations thereof. The method of any of claims 16-17, further comprising: prior to blending the matrix polymer with the impact modifier, polymerizing 40 to 90% of the acrylate monomer with 1 to 30% of the functional monomer to form a copolymer; and polymerizing the copolymer with 1 to 50% of the at least one copolymerizable monomer to form the impact modifier. The method of claim 18, wherein the acrylate monomer is butyl acrylate. The method of any of claims 18 or 19, wherein the at least one copolymerizable monomer is selected from the group consisting of (meth)acrylates, methyl methacrylate, butyl methacrylate, styrene, alpha methyl styrene, acrylonitrile, and combinations thereof. The method of any of claims 16-20, wherein the functional monomer is glycidyl methacrylate.