Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/06—Polyethene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/10—Homopolymers or copolymers of propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L27/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers
  • C08L27/02—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L27/04—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing chlorine atoms
  • C08L27/06—Homopolymers or copolymers of vinyl chloride
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L97/00—Compositions of lignin-containing materials
  • C08L97/005—Lignin
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2327/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers
  • C08J2327/02—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment
  • C08J2327/04—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment containing chlorine atoms
  • C08J2327/06—Homopolymers or copolymers of vinyl chloride
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2201/00—Properties
  • C08L2201/06—Biodegradable
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2203/00—Applications
  • C08L2203/16—Applications used for films

Definitions

• Polymer blending has become one of the most commercially important and inexpensive ways of developing new materials from readily available base polymers.
• the main aim of polyblending is the production of good performance materials at a reduced cost or the modification of some specific properties of polymers. This is achieved through the infinite blending possibilities, the ability to use existing flexible processing equipment, and the capacity to combine expensive polymers with ordinary and abundant ones.
• Polyethylene is produced by polymerizing ethylene gas and the result is a joining together of the ethylene molecules into long polymer chains.
• the most common additives are heat and light stabilizers, slip, antiblock and antistatic agents, flame retardants and pigments. To protect against thermal oxidation which can be a problem during processing, antioxidants are usually added. Photo or light oxidation that occurs when natural PE is exposed to UV radiation is most often inhibited by the addition of carbon black and/or UV stabilizers.
• PE is classified as either low and medium density (LDPE and LLDPE) or high density (linear) PE (HDPE) based on ASTM designation.
• LDPE and LLDPE have been used in several applications: film and sheeting, housewares, closures and containers, packaging materials, wire and cable coating, rotational molding, powder coating, pipe extrusion, refuse or garbage bags and extrusion coating.
• the primary processing techniques used to convert HDPE into end products are blow and injection molding for containers and lid closures, films and large containers.
• Ethylene(vinyl) acetate (EVA) copolymer is generally obtained by adding vinyl acetate to PE.
• EVA is tougher, more flexible, softer and less heat resistant then LDPE. Being softer and more flexible than PE, the copolymers are often competitive with rubbers and plasticized PVC. At higher levels of comonomer incorporation, the EVA's are used as wax additives and as components in other formulations for hot melt coatings and adhesives. In these applications, the copolymers provide strength, improved barrier properties and better processing characteristics.
• Polypropylene (PP) in its natural form is particularly vulnerable to degradative attack by oxygen and sunlight. Stabilizers have been developed which allow PP to retain its balance of good mechanical properties at low cost, and to do so in severe environments.
• Phenolic antioxidants have the primary function of reacting with the polymer peroxy radicals to form more stable radicals, and thus stop the chain oxidative attack.
• UV absorbers are added before processing. These absorbers are colorless and transform UV radiation into harmless longer wavelength light.
• Common classes of UV additives include the benzophenones, benzotriazoles, salicylates, and phenyltriazines.
• Certain nickel salts also provide some degree of UV absorption and act as a free radical scavengers, preventing the propagation of the photo-chain degradation process.
• PP finds applications in molded products for automotive and appliance uses, packaging, fibers and fibrillated films, microporous filters and desalinization equipments, spun fibers, film and sheet and nonwovens.
• Styrene is used primarily for the manufacture of thermoplastic resins, of which polystyrene (PS) and polystyrene copolymers are the most important.
• PS polystyrene
• Polystyrene is the third most widely used thermoplastic resin, surpassed only by PVC and PE. Most polystyrene is
• PVC is the most highly modifiable plastic known. Products can be formed with a broad range of mechanical properties. Being self-extinguishing, PVC also has inherent flame resistance. Plasticizers such as phtahlates and adipates contribute to its flexibility. The feel of PVC is controlled by the amount of plasticizers and/or filler material, as well as the type of resin. Impact modifiers can be included to increase breakage resistance.
• Ti2 titanium dioxide
• Ti ⁇ 2 is widely used in white and light color formulations. Ti ⁇ 2 is approximately 50% more costly than unplasticized PVC used for outdoor service and PVC producers are looking for ways to reduce their Ti0 2 consumption.
• thermoplastic polymeric materials are generally disposed of by incineration. They can also be disposed of by recycling which can be achieved by increasing their oxidation temperature. Increasing the oxidation temperature can be achieved through the use of additives. Such additives have generally been known to have certain other drawbacks as when such materials must be incinerated, such additives generate toxic fumes necessitating an additional treatment step which increases the overall cost of disposal. In any event, with PVC, additional treatment for effluent gases is necessary.
• thermoplastic polymeric materials can either photodegrade or biodegrade.
• photodegradable thermoplastic polymeric materials are obtained by introducing photoactive additives into a base material such as for example polyolefin. These additives consist of molecules containing oxygen and/or heavy metals which play a role in the initiation and formation of free radicals under the action of ultraviolet (UV) radiation. The free radicals cause a rupture of ⁇ • the chains of the polymer and therefore make the polymer fragile and mechanically degradable.
• UV radiation ultraviolet
• photoactive additives are generally strongly oxidizing which can cause the degradation of the plastic material to begin immediately after the manufacture of the material thus reducing the shelf life of the thermoplastic polymeric materials.
• biodegradable plastic materials can be obtained by the introduction of a biopolymer such as starch.
• a biopolymer such as starch.
• starch can be attacked by microorganisms, the material becomes susceptible to degradation.
• starch in such material can . have drawbacks as it can be partially decomposed during the processing and it is highly sensitive to water. Furthermore, starch is not compatible with most polymers, and its incorporation during polymer manufacture can render the final product brittle. Furthermore, in polymeric films with a particularly small thickness, the particle size of starch can be a limiting factor on the overall manufacturing process and the cost becomes prohibitive.
• biopolymers in addition to starch can also be used such as for example other carbohydrates with one major drawback , that upon blending with the polymeric material, the biopolymer can undergo various alterations such as oxidation and polycondensation. Such alteration to the biopolymer can have a negative effect on the mechanical properties of the polymeric materials.
• a biopolymer such as organosolv lignin can be incorporated with thermoplastic polymeric materials.
• This invention provides for degradable polymers and polymer products having incorporated therein an organosolv lignin.
• the incorporation of the lignin enhances the mechanical properties of the polymers while causing them to degrade under certain conditions.
• the polymers of this invention can be disposed of without incineration or recycled, resulting in a savings in energy and minimal pollution.
• the biopolymer employed in this invention is a lignin which is separated from plant biomass by a novel chemical delignification technology based on organic solvents, for example ethanol.
• organosolv lignin it is a free-flowing, non-toxic powder. It is soluble in aqueous alkali and in selected organic solvents. It is generally characterized by its hydrophobicity, purity, melt flow -properties and a low level of carbohydrates and inorganic contaminants.
• the lignins of this invention can be incorporated into various polymeric materials and can have various effects on the polymeric blend such as for example they can function as an antioxidant, as a stabilizer against ultraviolet radiation and can enhance the mechanical properties of these materials.
• the lignins of this invention can stimulate degradation of the polymeric materials when photoadditives are added to the blend.
• the products can degrade by photodegradation of the polymeric materials and the lignin or alternatively by biodegradation of the lignin under composting conditions.
• the lignins of this invention can be blended and compounded with polymers such as for example polyethylene, polypropylene, poly(vinyl) chloride and polystyrene copolymers in a weight ratio of from about 0.5% to about 40% with the polymer of choice.
• the blends can be then processed by extrusion, calendering, injection or known processes in the art to yield articles of manufacture having different utilities such as for example, film and molded products.
• the lignin can be blended with a copolymer such as for example ethylene (vinyl) acetate or styrene-butadiene copolymers.
• the resulting blend is a master batch which can be diluted by further blending with polymers such as for example polyethylene, polypropylene, poly(vinyl) choride and polystyrene copolymers.
• polymers such as for example polyethylene, polypropylene, poly(vinyl) choride and polystyrene copolymers.
• the blends can be processed using known methods in the arts to yield the desired final products.
• a master batch can be prepared by mixing with organosolv lignin of from 35% to about 85% on a weight basis with the copolymer of choice such as EVA, SBS or any other polymer which is known to have a glass transition temperature in the same range as that of the lignin.
• the master batch can be prepared by mixing all ingredients directly or in successive stages.
• the master batch can also be coextruded with a polymer of choice depending on the desired final product.
• Pellets can be produced with a core and a sheath with a variable composition.
• the core of the pellet can have the composition of the master batch while the sheath can have the polymer composition of the intended final product.
• the pellets can generally be obtained by granulating the filaments coming out of the extruder.
• the core of the pellet can be manufactured by considering the nature of the biopolymer to be incorporated therein.
• organosolv lignin When organosolv lignin is used, the pellet can be manufactured without causing any chemical or physical deterioration by mixing the lignin or a master batch polymer of particular interest such as for example EVA or SBS or any other master batch polymer which is known to have a glass transition temperature in the same range as that of the lignin.
• the core which comprises of from about 35% to about 85% lignin and 65% to 15% master batch polymer can be extruded at a temperature of from about 115°C to about 145°C to form a polymer sheath having a similar composition as the final product.
• Extrusion of the sheath generally requires a temperature of from about 170° to about 230°C.
• the overall composition of the coextruded compound is preferably equivalent to the composition of the finished product.
• the thickness of the sheath can be adjusted according to the diameter of the core which corresponds to the diameter of the central filament such that the level of lignin in the final coextruded product is of from about 0.5% to about 40%.
• the sheath thickness is of from about 4 mm to about 5 mm such that every individual pellet of compound comprises from about 4% to about 25% of lignin.
• An advantage of using coextrusion at the compounding temperature of polyethylenes and polypropylenes is that the problem associated with the thermal decomposition and oxidation of the biopolymer is alleviated.
• the coextruded compound upon extrusion takes on the appearance of pellets which are heterogeneous under the microscope but still are more homogeneous overall by contrast to the appearance of pellets which result from the mechanical mixing of two different pellet compositions.
• the master batch of this invention can be processed by extrusion, blowing, injection or other processes known in the art.
• the machinery generally used requires adaptation to the processes of this invention to meet the shorter residence times which are required at critical temperatures such as for example the oxidation temperature.
• the processes of the invention can operate at a lower temperature mainly because of the additional heat protection from the sheath to the lignin-rich core which is easier to melt and the viscosity of which is not as sensitive to the temperature as the PE or PP.
• organosolv lignin powder with a median particle size of from about 0.1 micron to about 100 microns and in a quantity of from about 0.5% to about 40% can be mixed with polyethylene or more generally an ethylene copolymer to manufacture homogeneous films having a thickness of from about 5 microns to about 100 microns.
• the polyethylene blends can be prepared by direct mixing or by using a master batch preparation. It has been observed that the resulting films can degrade when iron stearate or any other photoactive and/or oxidizing additives such as cerium salt is added in a range dependent on the target film shelf life and the conditions under which the film will be used.
• a preferred range is of from about 0.1% to about 0.5% of salt based on total weight of polymer blend.
• the plastic films thus obtained can be used for many agricultural applications, as well as for the manufacture of plastic bags for refuse, shopping baskets, etc.
• the stiffness of the film is essential
• the lignin containing polyethylene film of the present invention appears particularly interesting to use since the degradation of the film over time is total, both for the surfaces which are outside the ground and for those which are buried inside the ground.
• the adsorption and absorption capacities of lignin, of essential oils, insecticides and the like will permit then a use of lignin as an additive for the new fungicidal, rat-killing or other properties.
• lignin can be utilized so that the lignin can be incorporated into the photoactive products prior to its mixture with the copolymers, which has the advantage of increasing the homogeneity and the degradability of the film.
• this lignin containing plastic film can be coextruded, and can therefore be a part of a composite film.
• the initial mechanical properties of the lignin containing degradable film of the present invention are comparable to those of a film which does not contain any lignin.
• the lignin thermally behayes by partially condensing with apparent fusion and without oxidizing in a temperature range of from about 125°C to about 200°C and on the other hand by oxidizing without condensation at about 160°C.
• the properties of the lignin are material to the processes of this invention. When the lignin condenses, it is believed that it is capable of generating water to approximately from about 1% to about 6% of its weight. Therefore, special attention must be given to eliminating water produced during the manufacture of the thermoplastic polymeric material.
• the lignin and polymer can be mixed in an extruder which can be either a single or double screw.
• the mixing is preferably performed in a vented extruder such that any water vapor formed from the lignin is eliminated.
• the extrusion conditions are dependent on the scale of the process.
• the rotation speed of the screw is an important parameter and is a function of the materials introduced upstream.
• the temperature profile is also an important element of the success of a good mix since the lignin must be protected from oxidation and thermal degradation. This can be accomplished by adding the lignin to the already molten polymer or by using the master batch described herein. Upon mixing with the lignin, the lignin behaves as a thermal antioxidant which results in an increase in the oxidation temperature of the polymer. An increase in the oxidation temperature of the mixture enables the recycling of such material thus permitting it to be melted again for reuse without degradation. In the case where the material can no longer be recycled and it may prove necessary to effectively incinerate the material, addition of the lignin is beneficial as the heating value of the lignin is equivalent to that of the polymer used, thus allowing its destruction by incineration.
• the polymer used when its oxidation temperature is about from 150°C to about 160°C. By contrast with about 10% lignin, the oxidation temperature is from about 185°C to about 195°C and with about 25% lignin, the oxidation temperature is from about 195°C to about 205°C.
• the oxidation temperature when the polymer used is polypropylene, the oxidation temperature is from about 210°C to about 220°C. By contrast with about 10% lignin, the oxidation temperature is from about 255°C to about 265°C.
• thermoplastic polymeric material of this invention can be used in applications known in the art for example in extrusion/blowing applications, calendering, injection molding to form films, plates, sheets, tubes, bottle caps, wrapping paper, car parts and the like.
• plasticizers such as styrene butadiene rubber, zinc stearate, soybean oil to name a few can be added during fabrication.
• thermoplastic polymeric materials cannot be perfumed
• the invention provides for the addition of perfume material because of the presence of lignin or any other biopolymer which can absorb such scent additives.
• lignin can be mixed hot or cold either alone or in conjunction with the thermoplastic polymeric material.
• the lignin can be treated by maceration in solvents containing essential oils before it is blended with the polymeric materials.
• a mixture of scents such as for example terpenes and citronella can be directly injected in one of the sections of the extruder during the manufacturing of the mixture.
• PVC can be blended on a weight basis with from about 0.5 to about 40% organosolv lignin with a specific gravity of about 1.27 and a median particle size of from about 0.1 micron to about 100 microns.
• the final PVC/lignin blends have stronger mechanical properties and can degrade under the effect of light.
• the PVC blends can be used in medical, food, fashion and home applications. The following sets forth one particular embodiment for the blending of PVC with organosolv lignin.
• PVC blends were prepared with the composition set forth in Table 2.
• the blends were prepared by melt compounding in a Haake Rheomix 600 equipped with roller blades at a temperature of about 195°C. The time of mixing was about 8 minutes at a speed of roller blades of about 65 rpm. PVC was added first and the lignin second after about 30 seconds. Several batches were prepared for each formulation and after melt mixing the obtained blends were ground to a particle size of from about 3 to about 5 mm. Sheets with a thickness of about 2 mm were molded by compression at about 195°C. After cooling with air and under pressure, the sheets were cut with a cutting die in shoulder shaped specimens for mechanical testing.
• the mechanical properties, tensile strength and elongation at break were measured before and after 5 days and 20 days of artificial weathering and were correlated with the properties of PVC controls. They were measured in accordance with 7ASTM D 638 using an Instron universal testing machine.
• the weathering of the samples was carried out using equipment known in the art such as a Q-Panel QUV.
• rain and dew are simulated by a condensation system and it contains a series of UV-A lamps with a peak emission at 343 nm and a spectral power distribution of from 295 to about 400 nm. All • the specimens were subjected to several cycles of 4 hours each of UV exposure at an equilibrium temperature of about 50°C alternating with condensation exposure at an equilibrium temperature of about 40°C.
• the number of days of accelerated weathering was 5 and 20.
• Table 3 shows the influence of lignin on the fusion characteristics the blends.
• the processability or the fusion characteristics of PVC blends is generally influenced by the type of resin and additives present.
• a change in formulation especially in the case of rigid PVC composition can affect the fusion characteristics of PVC blends and consequently their processability. Improper processability can have a negative effect on the mechanical properties of PVC and its weatherability. It has been found that the fusion characteristics of blends of PVC with lignin formulated with or without Ti ⁇ 2 present almost the same characteristics as PVC controls. One may conclude that the fusion characteristics of PVC-lignin blends in comparison with PVC controls are very close and the presence of lignin does not have a negative effect on the processability of PVC-lignin blends. The specimens of PVC lignin blends with Ti ⁇ 2 were colored from beige to tan and PVC lignin blends without Ti0 2 were dark brown.
• Table 4 shows the strain-stress data for PVC controls and PVC-lignin blends before and after 5 and 20 days.
• the lack of correlation between the values of the tensile stress-strain data predicted by the theoretical model elaborated by Nielsen (J. Appl. Polym. Sci., Vol. 10, 97-103 (1966)) particularly in the case of perfect adhesion between filler (in this case lignin) and polymer (in this case PVC) and the experimental values shown in Table 4 suggest a certain degree of interaction between the two polymers in the blend.
• up to a certain level of about 6.81% lignin acts as a reinforcing agent without having a negative impact on the elongation.
• the PVC blends without Ti02 and the PVC blends comprising lignin are characterized by a change in color observed only on the exposed side to UV light.
• the color changed from white-grey to reddish yellow and in the case of the PVC blends comprising lignin the color changed to lighter tones.
• the change in color after weathering is barely perceptible which is believed to be due to the effect of Ti ⁇ 2 on the weathering of PVC.
• the PVC blends of this invention can be formulated to achieve good weatherability by blending synergistic levels of Ti02 and lignin.
• lignin and Ti ⁇ 2 can be formulated together to further optimize the photochemical reaction of the lignin and Ti ⁇ 2 thus affecting the final photodegradability of the formulation.

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• Compositions Of Macromolecular Compounds (AREA)
• Biological Depolymerization Polymers (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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