Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F255/00—Macromolecular compounds obtained by polymerising monomers on to polymers of hydrocarbons as defined in group C08F10/00
  • C08F255/02—Macromolecular compounds obtained by polymerising monomers on to polymers of hydrocarbons as defined in group C08F10/00 on to polymers of olefins having two or three carbon atoms
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/46—Reaction with unsaturated dicarboxylic acids or anhydrides thereof, e.g. maleinisation

Definitions

• the present invention relates to maleated polypropylenes and to methods for producing maleated polypropylenes. More specifically, the invention relates to methods for producing maleated polypropylenes having a relatively high percentage of bound maleic anhydride moieties, and the maleated polypropylenes obtained from such methods.
• maleated polyolefins and in particular maleated polypropylenes, are known in the art and find use in a wide range of applications.
• maleated polypropylenes are useful for compatibilizing polymers, particularly polyolefins with various polar substrates, including polar polymers, mineral fillers, and the like.
• Such copolymers are also known for use in metal bonding adhesive compositions.
• maleic anhydride is grafted onto a polypropylene backbone by introducing maleic anhydride, or a precursor thereof, into a melt of polypropylene polymer, typically in the presence of a catalyst.
• maleated polypropylene is as a compatibilizing agent, particularly for polar substrates, fibers and filler.
• the present invention is directed to methods for advantageously producing maleated polypropylenes having a relatively high percentage of bound maleic anhydride, based on the total amount of maleic anhydride moieties present in the grafting reaction product, and the maleated polypropylenes produced therefrom.
• the methods of the present invention overcome the disadvantages of the prior art by facilitating the production of maleated polypropylenes wherein at least about 60%, and preferably at least about 75% of the maleic anhydride moieties in the grafting reaction product are bound to the polypropylene. Unless indicated otherwise herein, all percentages are intended to refer to weight percent.
• the improved process is characterized judiciously selecting the type and nature of the reactants used and adding maleic anhydride to the selected polypropylene, and preferably polypropylene melt, under time, temperature and pressure conditions effective to graft at least about 55 %, and even more preferably at least about 60 %, of maleic anhydride to the polymer backbone, said percentage being based on the total maleic anhydride moieties, including precursors thereto, present in the grafting reaction product.
• grafting reaction product refers to maleated polypropylene, together with any unreacted components, by products and impurities, after the grafting reaction is deemed to be substantially completed, but before any subsequent purification steps.
• polypropylene refers to and includes homopolymers of polypropylene and all forms of polypropylene copolymers, and in particular polypropylene- polyethylene copolymers, provided that at least about the majority of the polymer is formed of polypropylene moities on a mole percent basis.
• copolymer refers to and includes terpolymers and the like.
• the polyolefin reactant of the present invention is polypropylene homopolymer, or a copolymer of propylene and ethylene wherein the concentration by weight of ethylene is less than about 10%, and more preferably less than about 5%.
• the term "maleated polypropylene” refers generally to the reaction product formed by grafting maleic anhydride, preferably by covalent bonding, to the polymer backbone of polypropylene. As is known in the art, therefore, such grafting reaction products in commercial applications generally comprise not only maleated polypropylene but also as unbound maleic anhydride and oligomeric maleic anhydride.
• bound maleic anhydride refers generally to the moieties derived from maleic anhydride which are grafted to the polypropylene backbone according to the present invention.
• Unbound maleic anhydride refers generally to unreacted maleic anhydride or oligomeric anhydride present in the grafting reaction product.
• the grafting reaction product is generally the melt at the conclusion of the grafting reaction step.
• the maleic anhydride is introduced to the polypropylene, and preferably a polypropylene melt, at a rate that maintains the concentration of maleic anhydride in the reaction mixture (e.g., in the melt) at no greater than about 120 %, and even more preferably no greater than 100 %, of the solubility limit of the maleic anhydride in the polypropylene at the reaction conditions.
• grafting maleic anhydride to polypropylene in a reaction mixture wherein the amount of unreacted maleic anhydride in the mixture is maintained at a relatively low level is capable of producing a reaction product copolymer that either contains a very high level of bound maleic anhydride and/or contains a relatively low level of oligomeric maleic anhydride .
• the amount of maleic anhydride which is bound in the grafting reaction is generally related to the amount of polyethylene in the copolymer. More particularly, it is generally preferred that the copolymer comprise up to about 10 mole % polyethylene, more preferably up to about 5 mole % of polyethylene, and even more preferably from about 0.5 mole% to about 3 mole% polyethylene. Applicants have discovered that polyethylene levels as described herein help to produce the claimed high levels of bound maleic anhydride without negatively effecting the compatibalization properties of the reaction product.
• the present invention therefore provides an improved graft maleic anhydride/polypropylene copolymer product comprising polypropylene backbone, bound maleic anhydride and from about 0% to about 40% of unbound maleic anhydride wherein at least about 60 wt% of said maleic anhydride moieties, more preferably at least about 65wt% of said maleic anhydride moieties, and even more preferably at least about 70 % of said moieties are bound maleic anhydride, based on the total maleic anhydride moieties in the reaction product. In especially preferred embodiments, at least about 75 % of said moieties are bound maleic anhydride, based on the total maleic anhydride moieties in the reaction product.
• One aspect of the present invention is directed to methods for producing maleated polypropylenes comprising reacting maleic anhydride, or a precursor thereof, with polypropylene in a reaction mixture. It is contemplated that various particular process and unit parameters can be adapted for use with the present reaction step, and a wide range of known methods and steps for combining and reacting maleic anhydride and polypropylene in a reaction mixture can be used according to the present invention. For example, it is contemplated that processes of the present invention may comprise one or more of the classes of reaction procedures known in the art, including: melt grafting, solid state grafting, solution grafting, and the like. However, present invention is preferably conducted by melt grafting.
• the steps of the present invention may be conducted on a continuous basis, on a batch basis, or on a combination of both. Those of skill in the art will, in view of the teachings contained herein, be able to adopt the present invention to any of these modes of operation without undue experimentation.
• the amount of maleic anhydride which is bound in the reaction step of the present invention can be affected by numerous reaction parameters, including the nature of the polypropylene as described above, and applicants believe that it is highly advantageous to control one or more of the relevant parameters in accordance with teachings of the present invention in order to achieve a high level of bound maleic anhydride and/or low levels of unreacted and oligomeric maleic anhydride.
• the grafting reaction step of the present invention can be conducted under any combination of particular grafting reaction conditions, provided that the reaction of polypropylene with maleic anhydride is favored relative the reaction of maleic anhydride with itself or with other components in the reaction mixture, such as maleic anhydride oligomers.
• One preferred mechanism for obtaining a reaction mixture in which the polypropylene/maleic anhydride grafting reaction is highly favored is to maintain the concentration of unreacted maleic anhydride in the reaction mixture at relatively low levels compared to those levels used in prior art processes.
• applicants do not wish to be bound by or to any theory of operation, it is believed that the unexpectedly higher percentages of bound maleic anhydride found in the preferred products of the present method are achieved, at least in part, because maleic anhydride has a limited solubility in polypropylene, an in particular in a polypropylene polymer melt.
• use of a low concentration of maleic anhydride results in less phase separation in the reaction mixture between the maleic anhydride, or the precursors thereof and polypropylene.
• maleic anhydride concentrations that are not substantially greater than the solubility limit of the polymer has two distinct beneficial results.
• the present invention minimizes the amount of unreacted maleic anhydride exposed to conditions which favor anhydride/anhydride reaction, as would occur with the maleic anhydride that exists in a phase separate from the polymer phase. Lower phase separation therefore allows for binding of a higher percentage of the maleic anhydride introduced to the polymer melt.
• the initially formed, lightly maleated product is believed to help solubilize any additional maleic anhydride reactant that is subsequently introduced to the polymer melt in preferred embodiments of the present invention.
• the methods of the present invention comprise reacting maleic anhydride with polypropylene under conditions effective to maintain the concentration of unreacted maleic anhydride in the reaction mixture at less than about 2.5 %, more preferably less than about 2 %, and even more preferably less than about 1 %, during a substantial portion, and preferably during at least about 75%, of the grafting step.
• this grafting reaction step comprises adding maleic anhydride to a reaction mixture comprising polypropylene, and preferably a polypropylene melt, under conditions effective to maintain the concentration of maleic anhydride in the reaction mixture at less than about 2.5, more preferably less than about 2 %, and even more preferably less than about 1 % weight percent during a substantial portion, and preferably during at least about 75% of the adding step.
• the term "substantial portion" with respect to the reaction step and adding step refers to any portion or portions of the grafting reaction in which, in the aggregate, at least 50% of the maleic anhydride-polypropylene bonds are formed.
• the maleic anhydride is added to the reaction mixture at rate of less than about 0.045 pounds of maleic anhydride or precursor thereof ("MA") per pound of polypropylene (“PP”) per hour of grafting reaction conditions (MA/PP/hr), and even more preferably less than about 0.040 MA/PP/ hr.
• the molecular weight of the polypropylene used in the maleation process, as well as the maleic anhydride content of the maleated polypropylene, typically characterized by the saponification number of the final product affect the percent of bound maleic anhydride found in the final product.
• saponification number refers to the measure of the amount of saponifiable matter present, including bound single unit maleic anhydride, bound oligomeric maleic anhydride, unreacted maleic anhydride, unbound oligomeric maleic anhydride, and other hydrolyzable moieties, in the maleated polypropylene.
• the SAP is generally calculated as the number of milligrams of potassium hydroxide required to hydrolyze one gram of sample (mg KOH/g).
• Fig. 1 is a graphic depiction of the percent bound maleic anhydride plotted against the SAP of a low molecular weight polypropylene and a high molecular weight polypropylene. As illustrated in Fig.l, generally, the percent bound maleic anhydride decreases as the SAP increases. In addition, as the molecular weight of the polypropylene increases, the percent bound decreases. It is believed such variables are controlled in accordance with the present invention to produce useful maleated polypropylenes having high a percent of bound maleic anhydride.
• the molecular weight of the polypropylene reactant and the SAP of the reactant is preferred to select the molecular weight of the polypropylene reactant and the SAP of the reactant to achieve bound maleic anhydride in accordance with the present invention.
• the high molecular weight polypropylene has a SAP of no greater than about 70, more preferably no greater than about 75 and even more preferably no greater than 80.
• the polypropylene has a SAP of no greater than about 100, more preferably no greater than about 120 and even more preferably no greater than 150.
• maleic anhydride Any commercial grade of maleic anhydride, or a precursor thereof such as maleic acid (which is converted to maleic anhydride under many commonly used grafting reaction conditions) is suitable for use in the present invention.
• suitable maleic anhydrides include those that are is commercially available, for example, though Monsanto Company (St. Louis , NO) as Maleic Anhydride, and Huntsman Petrochemical Corporation (Chesterfield, MO) as Manbri Maleic Anhydride.
• Polypropylenes suitable for use in the present invention include those polypropylenes commercially available, for example, through Honeywell (Morristown, NJ) under the trade name ACX1089.
• the weight ratio of polypropylene to maleic anhydride used in the present method is from about 5:1 to about 40:1. More preferably the weight ratio is from about 5: 1 to about 25: 1, and even more preferably is from about 10:1 to about 20:1.
• the reacting step further comprises reacting the maleic anhydride with the polypropylene in the presence of a catalyst.
• a catalyst Any of a wide range of catalysts can be used in the present invention. Suitable catalysts include, for example, free radical forming agents known in the art and include, for example,
• dialkyl peroxides dialkyl peroxides, tertiary butyl hydroperoxide, cumene hydroperoxide, p-menthane peroxide,
• p-menthane hydroperoxide or axo compounds such as azobis (isobutyronitrile), or irradiation sources.
• the preferred free radical sources are the peroxides with the butyl peroxides being
• ditertiary butyl peroxide di-t-butyl peroxide
• the amount of peroxide or free radical agent used is generally quite low, being of the
• reaction at a rate of preferably about 0.01 to about 3 wt % of the starting material per hour
• the catalysts are added to the reaction mixture of
• the catalyst can be added simultaneously and/or separately in relation
• the maleic anhydride and catalyst are identical to the maleic anhydride.
• the maleic anhydride and catalyst are identical to the maleic anhydride.
• the maleic anhydride and catalyst are identical to the maleic anhydride.
• maleic anhydride and catalyst are added to the reaction mixture in overlapping
• the process of the present invention may further comprise the use of other additives in
• substantially hinder the formation of a product of the present invention may be used in suitable amounts.
• suitable additives include: comonomers, such as, styrene, chain transfer
• reaction of the present invention may be carried out under any suitable reaction
• the polypropylene comprise a polypropylene melt.
• the temperature of reaction be above the melt temperature of the polypropylene, but preferably no greater than about 200°C.
• reaction temperature is generally preferably between
• the reaction pressure depends, among other things, upon the reaction temperature and desired rate of reaction. Generally, the reaction is conducted under a pressures preferably from about 0 to about 50 psig, more preferably from about 5 to about 30 psig, and even more
• the grafting reaction of the present invention is conducted such that at least about 60wt% of maleic anhydride, based on total weight of maleic anhydride in the grafting
• reaction product is bound to the polymer backbone.
• reaction is conducted
• This example illustrates the production of a maleated propylene in accordance with the
• thermal degradation unit for an average contact time of 30 minutes.
• the thermal degrader is operated at a temperature of 370C with the agitator operated at a speed of such that all of the
• thermal energy for degradation is supplied by the friction of mixing. The degraded
• polypropylene wax has a melt viscosity of about 800 centipoise measured at 190C. This
• Example 1 weight of ditertiary butyl peroxide to a thermal agitated reactor maintained at about 200C to produce a reaction product mixture, and even after standard techniques for separating unreacted maleic hydride from the reaction mixture, had a concentration of bound maleic anhydride of less than about 50%.
• Example 1
• the reaction mixture is stirred for an additional 10 minutes.
• Standard techniques are used in an effort to remove unreacted maleic anhydride. More particularly, a vacuum of 25" Hg is applied to the grafting reaction product and periodic samples are removed and tested for unreacted maleic anhydride. The vacuum is removed and the reaction mixture is cooled to 170°C, and the grafting reaction product mixture after the standard vacuum purification comprises greater than 70%, and more preferably greater than about 80%, and even more preferably greater than 85% bound maleic anhydride.

Landscapes

• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Graft Or Block Polymers (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=23110793

Family Applications (1)

Country Status (7)

Families Citing this family (14)

Citations (2)

Family Cites Families (4)

• 2002
  • 2002-05-06 JP JP2002587479A patent/JP2005509688A/ja active Pending
  • 2002-05-06 CN CNB028135466A patent/CN100491427C/zh not_active Expired - Lifetime
  • 2002-05-06 KR KR1020087032048A patent/KR20090006238A/ko not_active Application Discontinuation
  • 2002-05-06 KR KR10-2003-7014465A patent/KR20030096358A/ko not_active Application Discontinuation
  • 2002-05-06 CA CA002446406A patent/CA2446406A1/en not_active Abandoned
  • 2002-05-06 KR KR1020107011678A patent/KR101040689B1/ko active IP Right Grant
  • 2002-05-06 AU AU2002309651A patent/AU2002309651B2/en not_active Expired
  • 2002-05-06 WO PCT/US2002/014320 patent/WO2002090403A1/en active Application Filing
  • 2002-05-06 EP EP02736665A patent/EP1434809A4/en not_active Withdrawn
• 2009
  • 2009-06-17 JP JP2009144373A patent/JP5718555B2/ja not_active Expired - Lifetime
• 2014
  • 2014-09-26 JP JP2014196793A patent/JP5837166B2/ja not_active Expired - Lifetime

Patent Citations (2)

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events