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
  • C08F2/00—Processes of polymerisation
  • C08F2/12—Polymerisation in non-solvents
  • C08F2/16—Aqueous medium
  • C08F2/22—Emulsion polymerisation
• • 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
  • C08F265/00—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
  • C08F265/04—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00 on to polymers of esters
• • 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
  • C08F2/00—Processes of polymerisation
  • C08F2/12—Polymerisation in non-solvents
  • C08F2/16—Aqueous medium
  • C08F2/22—Emulsion polymerisation
  • C08F2/24—Emulsion polymerisation with the aid of emulsifying agents
  • C08F2/26—Emulsion polymerisation with the aid of emulsifying agents anionic
• • 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
  • C08F265/00—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
  • C08F265/04—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00 on to polymers of esters
  • C08F265/06—Polymerisation of acrylate or methacrylate esters on to polymers thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
  • C08L51/003—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds
• • 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
  • C08F14/00—Homopolymers and 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
  • C08F14/02—Monomers containing chlorine
  • C08F14/04—Monomers containing two carbon atoms
  • C08F14/06—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
  • C08L2201/10—Transparent films; Clear coatings; Transparent materials
• • 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
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
  • C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure

Definitions

• the invention relates to a method for preparing vinyl chloride graft copolymers by emulsion polymerization, and to a method for producing blends of such graft copolymers.
• the invention also relates to transparent moldings (i.e. molded articles) manufactured by using the graft copolymers and their blends, respectively, according to the invention.
• Plasticized polyvinyl chloride does not belong to the group of thermoplastic elastomers (TPE) although it has TPE properties (PVC Handbook, Charles E. Wilkes, James W. Summers, Charles Anthony Daniels—2005, page 14). Due to the low costs for the raw materials, the multifaceted processing properties and the good product features it takes a special position among the thermoplastic elastomers. Plasticized PVC shows very good stretchability and tensile strength due to the formation of microcrystallites and the dipole-dipole interactions between chlorine and hydrogen atoms. By varying the percentage of plasticizer in PVC the rigidity and flexibility of a product can be adjusted in a very easy manner.
• oligomeric and polymeric plasticizers have been employed, which, due to their high molecular weights, show only little to none tendency to migrate (Domininghaus-Kunstscher, 7 th revised and extended edition 2008).
• Known examples are copolymers consisting of ethylene-vinyl acetate-vinyl chloride (EVA-VC), ethylene-vinyl acetate (EVA, Levapren®), acrylonitrile-butadiene (NBR), styrene-butadiene (SBR), ethylene-vinyl acetate-carbon monoxide (Elvaloy®), styrene-butadiene-styrene (SBS, Kraton®) etc.
• EVA-VC ethylene-vinyl acetate-vinyl chloride
• EVA ethylene-vinyl acetate
• EVA ethylene-vinyl acetate
• NBR acrylonitrile-butadiene
• SBR st
• the high-molecular weight plasticizers are blended with PVC or grafted with PVC in a suspension polymerization process. These products are only used for special requirements (low-temperature flexibility, low migration, fat resistance, etc.), since otherwise the disadvantages will prevail, such as low plasticizing, more complex processing, inferior tear resistance, etc. To be considered a particularly serious drawback is the fact that moldings which were produced from a blend of PVC and the majority of polymeric plasticizers (elastomers) are opaque.
• PBA-g-PVC graft copolymers described in the prior art and prepared in emulsion or suspension processes can only be processed into translucent or opaque moldings.
• Cross-linked polyacrylic esters can be employed to improve the notch impact strength of rigid PVC (EP 0472852).
• DE 3803036 a suspension process is described which allows to obtain a PVC that contains 65 wt % of a cross-linked PAE.
• This product can be employed as an impact resistance modifier or as a polymeric plasticizer for PVC.
• An object of the present invention is a method for producing a vinyl chloride graft copolymer by using emulsion polymerization, wherein the graft copolymer contains a graft base and a grafted copolymer phase, which at least partially consists of vinyl chloride, comprising the steps of:
• the glass transition temperature T g of the grafted copolymer phase typically lies in the range of above 20 to 120° C. and/or the one of the graft base in the range of ⁇ 80 to 20° C. In a preferred embodiment of the invention the glass transition temperature T g of the grafted copolymer phase lies between 40 and 90° C., and the one of the graft base between ⁇ 60 and ⁇ 20° C.
• the T g 's of the grafted copolymer phase and of the graft base result from the composition of the respectively used monomers.
• the vinyl chloride graft copolymers are prepared in an emulsion process.
• the graft base can be prepared by copolymerizing vinyl compounds.
• the grafted compound can be prepared from 60 to 100 wt % of vinyl chloride, preferably 80 to 100 wt %, and from 0 to 40 wt % of other polymerizable vinyl compounds, preferably 0 to 20 wt %.
• the graft base and/or the grafted copolymer phase are cross-linked.
• the emulsion polymerization is preferably carried out semi-continuously.
• water, initiators, monomers, emulsifiers and other additives can be pre-charged into a reactor and partly added in small amounts.
• water and the total amount of emulsifier are pre-charged and both the monomers and the initiators are added.
• the feeding speed of the additives is based upon the conversion speed.
• the duration of the polymerization is adjusted to one to three hours by the amount of the initiator employed.
• the graft base is processed and pre-charged for the preparation of the graft copolymer.
• Vinyl chloride and, if applicable, other polymerizable vinyl compounds, are added within 10 min to 180 min.
• the amount of VC is divided into a portion to be pre-charged and a portion to be added.
• 5 to 20 parts of VC are pre-charged (at once), then polymerized until the pressure drops, and then the addition of the residual amount of VC is started.
• the temperature is regulated to adjust the desired K-value.
• an initiator is added simultaneously.
• An emulsifier can be added to increase the stability of the dispersion.
• the content of solids in the fully polymerized dispersion lies between 20 and 60 wt %, and preferably between 30 and 55 wt %.
• Suitable vinyl compounds for the graft base are, for example, acrylic acid esters or methacrylic acid esters (in brief: (meth)acrylic acid ester). Also, butadiene, 2-chloro-butadiene, 1-butene, isoprene, vinylidene chloride, vinyl acetate, vinyl alkyl ether, etc. can be used as vinyl compound.
• preferably merely vinyl chloride is used for the grafting.
• (meth)acrylic acid esters which contain 1 to 12 carbon atoms in the alkyl chain of the esterified linear, branched or cyclic alcohol, such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, t-butyl acrylate, pentyl acrylate, isopentyl acrylate, cyclohexyl acrylate, ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, t-butyl methacrylate, pentyl methacrylate, isopentyl methacrylate, ethylhexyl methacrylate, cyclohexyl methacrylate, etc.
• step b) of the method according to the invention the copolymer phase is typically grafted by emulsion polymerization using at least one emulsifier, in which preferably 60 to 100 wt % of the emulsifier amount is pre-charged, based on the total amount of emulsifier.
• the polymerization temperature in the process of preparing each of the graft bases typically lies between 20 and 90° C., preferably between 60 and 95° C.
• the polymerization temperature in the process of preparing each of the grafted copolymer phases typically lies between 45 and 90° C., preferably between 55 and 70° C.
• the percentage of the graft base is preferably 5 to 70 wt %, and the percentage of the grafted copolymer phase is preferably 30 to 95 wt %, in each case based on the vinyl chloride copolymer.
• Suitable ionic emulsifiers are alkyl sulfonates, aryl sulfonates, alkyl sulfates, alkyl ether sulfates, fatty acid salts, diaryl sulfonates, etc. It is also possible to use non-ionic emulsifiers, such as alkyl ether alcohols having 2 to 20 carbon atoms in the alkyl chain and 1 to 20 ethylene glycol units, fatty alcohols, etc., alone or in combination with ionic emulsifiers. The total amount of emulsifier used lies between 0.1 to 5 wt %, based on the amount of monomers employed.
• Suitable initiators are water-soluble peroxides, which form radicals by thermal decomposition alone or which can be caused to decompose in combination with a reducing agent and, if necessary, a catalyst.
• the amount of the initiators employed usually lies between 0.01 and 0.5 wt %, based on the monomers employed.
• the graft base is cross-linked by copolymerization with one or more different monomers that contain two or more non-conjugated ethylenically unsaturated double bonds.
• both the graft base and the graft shell will not be cross-linked, or b) the graft base will not be cross-linked and the graft shell will be cross-linked.
• Suitable compounds for cross-linking are diallyl phthalate, allyl methacrylate, allyl acrylate, ethylene glycol dimethacrylate, propylene glycol dimethacrylate, butylene glycol diacrylate, trimethylene glycol diacrylate, glycidyl methacrylate, glycidyl acrylate, etc.
• a vinyl chloride graft copolymer-containing latex is obtained by way of emulsion polymerization.
• the solid will be separated either by adding an electrolyte, coagulation and mechanical separation methods such as filtration, decantation, centrifugation of the latex, followed by drying, or by spray drying.
• At least two different vinyl chloride graft copolymers are prepared independently of each other and mixed subsequently, giving a blend in which the at least two different graft copolymers differ from each other by their respective percentage weight distribution of the graft base and the grafted copolymer phase.
• the steps a), b), and c) and the blending are carried out in such a way that the blend contains:
• steps a), b) and c) and the blending are carried out in such a way that a blend is obtained consisting of:
• an object of the invention is a vinyl chloride graft copolymer prepared according to the method described above.
• a further object of the invention is a blend that contains different vinyl chloride graft copolymers prepared according to the method described above.
• an object of the invention is an article prepared by using a vinyl chloride graft copolymer prepared according to the method described above or by using a blend that contains different vinyl chloride graft copolymers prepared according to the method described above.
• Preferred articles according to the invention have a transmittance of at least 65%, preferably of at least 75%, and particularly preferred of at least 85%, and/or a haze value of at most 60, preferably of at most 50, and particularly preferred of at most 40.
• an object of the invention is the use of a vinyl chloride graft copolymer and the use of the blends described above for manufacturing an article, preferably for manufacturing films by way of extrusion and/or calendering or for manufacturing molded articles by way of extrusion or injection molding or other thermoplastic molding methods.
• the average volume-based particle size (PSV) was 12 nm.
• the solid content of the dispersion was 30.7 wt %, the surface tension was 56.7 mN/m, the pH was 7.7.
• the average volume-based particle size was 61 nm.
• the preparation was precipitated with calcium chloride and filtered by suction filtration. The residue was dried at 30° C. in a recirculating-air dryer to a residual moisture of ⁇ 0.3% and finely ground with a centrifugal mill (Retsch ZM 200).
• the PBA content was determined to be 46.9 wt % by an oxygen analysis.
• Example 1 The graft base of Example 1 was used.
• the solid content of the dispersion was 30.5 wt %, the surface tension was 58.5 mN/m, the pH was 8.0.
• the average volume-based particle size was 58 nm.
• the preparation was precipitated with calcium chloride and filtered by suction filtration. The residue was dried at 30° C. in a recirculating-air dryer to a residual moisture of ⁇ 0.3% and finely ground with a centrifugal mill (Retsch ZM 200).
• the PBA content was determined to be 33 wt % by an oxygen analysis.
• Example 1 The preparation of Example 1 was repeated. 7909 g of an aqueous dispersion were discharged. The solid content of the dispersion was 30 wt %, the surface tension was 54.4 mN/m, the pH was 7.4. The average volume-based particle size was 12 nm.
• the average volume-based particle size was 92 nm.
• the preparation was precipitated with calcium chloride and filtered by suction filtration.
• the residue was dried at 30° C. in a recirculating-air dryer to a residual moisture of ⁇ 0.3% and finely ground with a centrifugal mill (Retsch ZM 200).
• the PBA content was determined to be 41.1 wt % by an oxygen analysis.
• the interior reactor temperature was maintained for 60 min and the preparation was cooled down subsequently. 6963 g of the dispersion were discharged, having a solid content of 29.6 wt %, the surface tension was 56.4 mN/m and the pH was 8.1. The average volume-based particle size was 74 nm.
• the preparation was prepared following Example 1.
• the solid content of the dispersion was 32.4 wt %, the surface tension was 48.8 mN/m, the pH was 8.0.
• the average volume-based particle size was 131 nm.
• the preparation was precipitated with calcium chloride and filtered by suction filtration.
• the residue was dried at 30° C. in a recirculating-air dryer to a residual moisture of ⁇ 0.3% and finely ground with a centrifugal mill (Retsch ZM 200).
• the PBA content was determined to be 50.0 wt % by an oxygen analysis.
• the samples according to the invention can be processed to transparent press plates.
• the samples according to the invention are characterized in that both the graft base and the graft shell are non-cross-linked, or that the graft base is non-cross-linked while the graft shell is cross-linked, or that the average particle size is below 150 nm when both the graft base and the graft shell are cross-linked, or when only the graft base is cross-linked while the graft shell is non-cross-linked.
• the interior reactor temperature was maintained for 60 min and the preparation was cooled down subsequently. 6925 g of the dispersion were discharged, having a solid content of 29.6 wt %, a surface tension of 52.6 mN/m and a pH of 8.2.
• the average volume-based particle size was 135 nm.
• the preparation was prepared following Example 1.
• the solid content of the dispersion was 28.3 wt %, the surface tension was 42.5 mN/m, the pH was 8.4.
• the average volume-based particle size was 176 nm.
• the preparation was precipitated with calcium chloride and filtered by suction filtration.
• the residue was dried at 30° C. in a recirculating-air dryer to a residual moisture of ⁇ 0.3% and finely ground with a centrifugal mill (Retsch ZM 200).
• the PBA content was determined to be 49.6 wt % by an oxygen analysis.
• the preparation was prepared following Example 1.
• the solid content of the dispersion was 26.3 wt %, the surface tension was 40.8 mN/m, the was pH 8.8.
• the preparation was precipitated with calcium chloride and filtered by suction filtration.
• the residue was dried at 30° C. in a recirculating-air dryer to a residual moisture of ⁇ 0.3% and finely ground with a centrifugal mill (Retsch ZM 200).
• the PBA content was determined to be 52 wt % by an oxygen analysis.
• the average volume-based particle size was 224 nm.
• the solid content of the dispersion was 27.1 wt %, the surface tension was 38.8 mN/m, the pH was 8.2.
• the preparation was precipitated with calcium chloride and filtered by suction filtration. The residue was dried at 30° C. in a recirculating-air dryer to a residual moisture of ⁇ 0.3% and finely ground with a centrifugal mill (Retsch ZM 200).
• the PBA content was determined to be 56.6 wt % by an oxygen analysis.
• the average volume-based particle size was 336 nm.
• the powdered graft copolymers were processed and pressed into rolled sheets.
• Table 1 the poly(butyl acrylate) content, the degree of cross-linking, the particle sizes of the graft copolymers and the optical properties (transmittance, haze) are given.
• the particle size distributions were measured with a Microtrac Blue-Wave of the S3500 series by Particle-Metrix.
• the valid measuring range lies between 0.01 and 2000 ⁇ m.
• a standard procedure for dispersions was created, where certain physical properties of the dispersion were given.
• three drops of Hellmanex® by Hellmanex-Analytics Inc.
• the cleanliness of the measurement system was validated by a baseline measurement. Dispersion was added carefully to the sample unit until a loading factor of about 0.004 was reached. Normally, 1 or 2 drops of dispersion are sufficient.
• the measurement time was 30 s. Evaluation of the measurement is carried out automatically.
• the average volume-based particle size is used.
• test samples have to be provided.
• the preparation of the rolled sheets is performed under the following conditions.
• the powder compound is placed onto the roller. After formation of the sheet, it is “cut” and “turned” for 3 min. Then set the thickness of the rolled sheet to 1.1 mm and continue to plasticize on the roller for further 2 min without cutting and turning. When the specified rolling time is over, the rolled sheet is taken off.
• the previously rolled sheets were cut corresponding to the frame size used, inserted into the frame and placed into the laboratory press together with the press plates that form the outer surfaces.
• the sheets are formed into a press plate under the conditions described below.
• the sample to be measured is illuminated perpendicularly and the transmitted light is photoelectrically measured in an integrating sphere.
• the perpendicularly transmitted light is measured in order to evaluate the transmittance, and the light that is scattered in an angle of 2° to the axis of irradiation is measured to evaluate the opaqueness (haze).
• the measurements are carried out according to ISO 13468. This guarantees that the measurement conditions are the same during calibration as well as during measurement.
• the graft copolymers Vinnolit VK 710 and Vinnolit K707 E, having an acrylate content of about 50 wt %, represent the prior art. Especially due to the high haze value (which characterizes the large-angle scattering), the press plates appear translucent to opaque. The examples according to the invention have a considerably better transparency, which features a substantially lower scattering. The test and comparative samples prove the effect of particle sizes of the graft copolymers on the transparency of the PVC articles made therefrom.
• the Examples 8 to 12 according to the invention have a higher transparency than the Comparative Examples 1 to 3, which are cross-linked in the same manner and which have particle sizes of above 170 nm.
• the transparency of a press plate made therefrom will be improved substantially by reducing the particle size to below 200 nm.
• Blends consisting of the graft copolymers according to the invention that differ from each other in their PBA content have a higher transparency than Comparative Examples 1 to 4.
• blends of a transparent graft copolymer with S-PVC are opaque.

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• Organic Chemistry (AREA)
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• 2013
  • 2013-02-11 EP EP13704922.7A patent/EP2953981B1/de active Active
  • 2013-02-11 US US14/767,257 patent/US20160075811A1/en not_active Abandoned
  • 2013-02-11 RU RU2015138701A patent/RU2622383C2/ru active
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