CA1280544C - Vesiculated polymer granular compositions and paper made therefrom - Google Patents
Vesiculated polymer granular compositions and paper made therefromInfo
- Publication number
- CA1280544C CA1280544C CA000515822A CA515822A CA1280544C CA 1280544 C CA1280544 C CA 1280544C CA 000515822 A CA000515822 A CA 000515822A CA 515822 A CA515822 A CA 515822A CA 1280544 C CA1280544 C CA 1280544C
- Authority
- CA
- Canada
- Prior art keywords
- granules
- vesiculated
- composition
- diameter
- microns
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
- D21H21/50—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by form
- D21H21/52—Additives of definite length or shape
- D21H21/54—Additives of definite length or shape being spherical, e.g. microcapsules, beads
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
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- Paper (AREA)
Abstract
Abstract "Vesiculated Polymer Granular Compositions and Paper Made Therefrom"
An aqueous composition which comprises vesiculated polymer granules and a retention aid; said granules having a mean diameter of 1 to 500 microns, the ratio of the granule diameter to the mean vesicle diameter being at least 5:1, the maximum diameter of the vesicles being 20 microns and the volume of the vesicles being from 5-95% of the volume of the granules. These compositions are used in conjunction with fibrous cellulosic or non-cellulosic materials for the preparation of paper containing the vesiculated polymeric granules dispersed therein. The paper has improved optical opacity.
An aqueous composition which comprises vesiculated polymer granules and a retention aid; said granules having a mean diameter of 1 to 500 microns, the ratio of the granule diameter to the mean vesicle diameter being at least 5:1, the maximum diameter of the vesicles being 20 microns and the volume of the vesicles being from 5-95% of the volume of the granules. These compositions are used in conjunction with fibrous cellulosic or non-cellulosic materials for the preparation of paper containing the vesiculated polymeric granules dispersed therein. The paper has improved optical opacity.
Description
80~
This invention relates to the use of vesiculated polymer granules as a means of providing high opacity in fibrous materials and, more particularly, to compositions comprising said granules ?..,d fibrous cellulosic material of use in papermaking.
The development of fibrous systems having a high opacity has always been a concern to paper manufacturers.
Paper i8 typically made from fibrous cellulosic or non-cellulosic material which may have been delignified and/or bleached, e.g. plant matter, such as trees, cotton, bagasse, and synthetic polymers, such as rayon. To the aqueous fibrous suspension are generally added sizing materials, wet and dry strength additives, defoamers, biocides, dyes, and particularly, retention aids and fillers. The suspension (furnish) is transferred to a forming wire for water drainage to concentrate solids, and subsequently dried to the desired basis weight.
The function of retention aids is to improve the amount of fibrous material, fillers and fines retained by the forming paper sheet, whereas fillers are used to impart suitable optical properties, namely, whiteness, brightness, opacity, and colour.
The degree of opacity of a particular substrate is the result of diffuse light-scattering which occurs when visible radiation is reflected from particles on the surface of the -2- ~L280~i44 substrate and in the substrate medium itself. It has been customary to use high density inorganic mineral fillers, such as calcium carbonate and certain clays, to enhance the opacity of paper sheets. However, the use of such fillers has many disadvantages in the manufacture of paper.
In most cases the use of such inorganic mineral opacifying materials greatly adds to the weight of the paper. This added weight is not desirable with the increasing market demands for production of light-weight paper without loss of opacity.
Also, there is a practical limit to the amount of inorganic mineral filler which can be added to the paper owing to the fact that as the inorganic filler content increases there is a substantial loss of the paper web strength as the tensile strength decreases. This is caused by the interference with the hydrogen bonding between fibrous materials and because with increased inorganic mineral filler content there is less fiber present in the paper sheet to contribute to the strength.
In addition, the generally low retention of the inorganic mineral opacifiers in the paper results in a financial loss by virtue of the by-product waste produced from the wire during sheet formation. More importantly, this poor retention may result in contamination of streams, lakes and other waterways.
Added to the foregoing disadvantages in the use of these inorganic mineral fillers in paper, most inorganic mineral fillers possess a low opacity-to-weight ratio when included in paper.
It is also customary to incorporate in the dilute paper furnish, just before formation on the wire, small amounts of polyelectrolyte retention aids to give improved retention of the inorganic mineral fillers on the wire during sheet formation. For instance, British Patent No. 883l973 ~2~30544 describes the use of trace amounts of a water soluble non-cationic linear vinyl polymer having a molecular weight of at least 5 x 106 and mainly composed of carbamoyl-alkylene linkages containing not more than four carbon atoms, being added to the filler-containing aqueous suspension of cellulose fibers prior to sheet formation, as a retention aid.
Canadian Patent No. 1,046,815 describes a method of manufacturing paper sheet by means of the formation of filler/polymer conglomerates formed by contacting in an aqueous medium a mineral filler with a water soluble polymer having a molecular weight of at least 2 x 106 and possessing a zeta potential of -40 to +40 millivolts.
British Patent No. 1,353,015 describes a method of coating calcium carbonate particles with a selected gellable hydrophilic organic material and thereafter causing the said material to gel so as to form aggregates of gelled hydrophilic material and calcium carbonate particles. Under certain conditions aggregates of a fibrous character may be formed. The use of the coated calcium carbonate filler is stated to give a slightly increased retention without reducing the paper strength.
It has also been suggested that microencapsulated polymers can be incorporated in a paper sheet to enhance opacity. These substantially spherical polymers can be added in the dilute paper furnish before formation on the wire as substitutes for inorganic mineral fillers. These microcapsular opacifiers can also be incorporated in coatings for fibrous or non-fibrous substrates. For example, Canadian Patent No. 856,861 describes polymer granules with a vesiculated structure that can be utilized in a coating composition and polymer films to impart an opacity which is greater than non-vesiculated granules of the same composition.
-4- lZ805~4 u.s. Patent No. 3, 853, 579 and 3, 779, 800 describe a light-weight coating comprising a binder and small colourless plastic, polymeric particles which remain discrete and retain a diameter of about one wave length of visible light. The coating comprising the above mentioned materials may then be applied to a paper substrate in a conventional manner.
U.S. Patent No. 3,816,169 describes a coating of discrete, substantially spherical, air-containing microcapsules having substantially continuous organic, polymeric, solid walls, an average particle diameter of below 2 microns and having pigment particles incorporated in the microcapsular structure. The coating comprising the above mentioned materials may be applied on fibrous and non-fibrous substrates.
It is an object of this invention to provide a means for increasing the opacity of fibrous paper sheets, without significantly increasing the weight of said paper sheet to an extent not heretofore possible.
It i8 another object of this invention to improve the optical property of opacity without decreasing the web strength of a paper compared to a paper made with conventional inorganic mineral fillers.
Still another object of the present invention is to provide a reduction in the amount of opacifier which is lost during the formation of paper on the forming wire.
It is also an object of the present invention to provide a means for increasing the retention of pigmented and/or non-pigmented vesiculated granules.
~hus, it is a primary object of the present invention to provide an aqueous fibrous composition suitable for conversion to a sheet or roll of paper having reduced amounts of opacifying material, particularly pigment.
Accordingly, the invention provides an aqueous composition for use with a fibrous cellulosic or ~280S~A
non-cellulosic material, said composition comprising vesiculated polymer granules and a retention aid; said granules having a mean diameter of 1 to 500 microns, the ratio of the granule diameter to the mean vesicle diameter being at least 5:1, the maximum diameter of the vesicles being 20 microns and the volume of the vesicles being from 5-95~ of the volume of the granules.
By vesiculated polymer granules is meant granules of polymer, preferably spheroidal granules, which have a cell-like structure, the walls of which are provided by the polymer. The granules comprise a plurality of cells or vesicles, that is they are not mono-cellular or balloon-like, and although the vesicles are not necessarily of uniform size, the ratio of the diameter of the granule to the mean individual vesicle diameter is generally at least 5:1. The vesicles typically occupy from 5 to 95% of the total volume of the granules. Low vesicle volumes are usually associated with granules of high mechanical strength which are particularly useful for some applications, but to achieve the most useful opacifying effects the vesicles typically occupy at least 20~ of the total volume of the granules, preferably 20-75% of the volume.
Preferably, each vesicle as hereinbefore described should be enclosed in a continuous shell of polymer. If the granules are produced directly in their required physical size and shape, e.g. by a suspension polymerization process, there will be a random distribution of imperfect vesicles formed therein. On the other hand, if the granules are prepared by, for example, the mechanical degradation of bulk vesiculated polymer, substantially all of the vesicles adjacent to the outer surface of the granules will be imperfect; that is, part of the shell of polymer which preferably encloses them will be broken away.
Although the shape of the granules is not critical in achieving some increase in opacity we have found that spheroidal structure gives the best results.
. , .
-6- ~28054A
The term "retention aid" is a well-known term in the pulp and paper art and means a material that has a coagulating or flocculating effect or an electrochemical interaction on the fibrous material used as the major component of paper to effect increased retention of the fines of the fibrous material, pigment and the like.
Embraced with this term are the three main categories of retention aids, namely, inorganic salts, organic polyelectrolytes of the non-ionic, cationic, anionic and amphoteric types; and natural organic polymers, e.g.
starches and gums. Examples of inorganic salt retention aids are alum and sodium aluminate. Examples of organic polyelectrolytes include polyacrylamides, polyethylene-imines, polyamines, polyamideamines, of high, medium, and low molecular weights. Also, included are quaternized organic polyelectrolytes or natural organic polymers or quaternized non-ionic, cationic, anionic and amphoteric derivatives thereof.
Examples of retention aids of use in the practice of the invention include:
quaternized polyacrylamide (Q-PAM) polydiallyldimethyl ammonium chloride (DAD-MAC) dimethylamine epichlorohydrin (DMA-EPI) ALUM-aluminum sulfate (A12(SO4)3 18H20) Thus, we have now found in accordance with the present invention that polyelectrolyte retention aids have the capability of adhering thereto pigmented and/or non-pigmented vesiculated granules. It is believed that the aforementioned granules are retained in position on the fibers by attractive forces such as electrostatic attraction between the vesiculated granules, fibers and the retention aid by bridging effects. Such conglomerates can be used in the manufacture of paper sheet in order to increase the vesiculated granule content of the sheet. S~rprisingly, it has been found that when these pigmented and/or -7- ~28~54~
non-pigmented vesiculated granules are incorporated into aqueous paper pulp with the polyelectrolyte retention aid added to the furnish before being formed into a paper sheet on the forming wire, the resulting paper sheet achieves an opacity increase heretofore unobtainable.
Thus, in a further feature the invention provides an aqueous composition as hereinbefore defined further comprising a fibrous cellulosic or non-cellulosic material in the form of a paper pulp.
The invention is also of use when inorganic mineral pigment fillers are present in the paper.
The vesiculated granule opacifiers of use in the present invention comprise granules of polymer, essentially spheroidal, which have a cell-like structure, the walls of which are provided by the polymer. This cell-like structure is what is referenced to by the term vesicle. The granules are comprised of many vesicles, that is they are not mono-vesiculated or balloon-like, and although the vesicles are not necessarily of uniform size, the ratio of the diameter of the granule to the mean individual vesicle diameter should be at least S:l. The vesicles should occupy from 5 to 95% of the total volume of the granules. Low vesicle volumes are usually associated with granules of high mechanical strength which are particularly useful for some applications. To achieve the most useful opacifying effects we prefer that the vesicles occupy at least 20% of the total volume of the granules, preferably 20-75% of the volume.
The granules have substantially continuous, solid walls and have a predetermined particle size. Broadly, the granules may have a mean diameter of 1 to 500 microns. In general we find that granules having a mean diameter of 1 to 100 microns are of the most value as opacifying agents.
Preferably, when used as opacifying agents, essentially no granules should exceed the upper dimension limits by more than 20 microns. It is to be understood that the above -8- 1~80S4~
limits may be exceeded by a minor portion of granules which lie outside the stated dimensions.
The term "substantially continuous solid walls", as employed herein, is intended to include solid walled granules which are still sufficiently porous to permit the escape of vaporizable material in gaseous form therethrough upon the application of heat. Ideally each vesicle should be enclosed in a continuous solid wall of tightly cross-linked polymer, but it is not always essential to achieve this. For example, if the granules are produced by an emulsion process, there will be a random distribution of imperfect vesicles formed within the granule. As a further example, if the granules are prepared by the mechanical degradation of bulk vesiculated polymer, it is possible that lS many of the vesicles contiguous with the outer surface of the granule may be imperfect. This may be observed as vesicles with part of the wall of polymer which preferably encloses them broken away.
The vesicles, which are usually spherical in shape, should have a diameter of less than 20 microns and preferably less than 5 microns. The maximum diameter will clepend to a degree on the average diameter of the granule.
We have found that the opacifying effect of the granules tends to increase as the diameter of the individual vesicles decreases. The optimum light scattering effect of vesicles containing air is achieved in the range of 0.2 - O.S micron diameter.
The vesicles may be essentially gaseous; that is, they may be bubbles of air or other gas. In aqueous compositions they may be saturated with vapour, for example, with vapour diffusing into the vesicles, through their polymeric walls from the liquid medium in which the granules are suspended, or may be at least partially filled with liquid taken in from the liquid medium in which the granules are suspended.
When the granules are to be used in a paper sheet, we prefer -9- 1280~44 that most of the liquid in the vesicles be sufficiently volatile to diffuse out of the granules in contact with air.
That is, when the paper sheet has been formed on the wire and is then dried in air, or optionally at an elevated drying temperature, the granules provide essentially gaseous vesicles and in this form contribute an opacifying effect to the paper sheet.
In a further feature of the invention, the vesicles contain particulate solids. The particulate solids may be dispersed therein in a liquid in which the polymer is insoluble or may be associated with essentially gaseous components alone. For example, the particulate solids used in the granules may be any suitable organic or inorganic pigment. Such pigments include those finely divided materials which have been conventionally employed for the purpose of enhancing optical properties, such as opacity, in a paper sheet. Suitable pigments include, for example, Ti02, CaCO3, A12O3 3H2O, barytes (BaSO4), clay, ZnO, ZnS, CaSO3, CaSiO3, talc, and the like. Preferred inorganic pigments for the purpose of the present invention are TiO2, CaCO3, A12O3-3H2O, BaSO4, clay and ZnO, with titanium dioxide being particularly preferred.
Any desired pigment particle size may be used, as long as it i~ suitable for incorporation into the vesicular structure. Thus, for example, titanium dioxide having a mean particle size between 0.1 and 0.35 micron is highly suitable for the purposes of this invention.
The invention is not limited, however, to the use of the above types of pigment and unusual effects may be produced in a paper sheet by the use of granules in which the pigment is at least in part coloured. For example, the pigment may comprise iron oxide, phthalocyanine, quinacridone, cadmium sulphide, or u.v. brighteners.
Chemical or physical tagging agents may be included in the vesicles or in the polymeric cellular material dyes, u.v.
-10- ~8~)S~4 absorbers, u.v. brighteners, fluorescent materials and like additives.
The particulate solids need not be pigments in the generally understood meaning of the term. For example, the particulate solids may be extenders, e.g. bentonite or clays.
The particulate solids may be dispersed in a suitably volatile liquid which subsequently diffuses out of the granules to leave the dry particulate solids therein. We limit the particulate solids concentration for the purposes of this invention to a maximum of 60% by volume of the vesicle and while the size of the chosen particles depends on the actual vesicle diameter, we prefer that the maximum particle diameter should be 1 micron.
It is a particular feature of the present invention that when these particulate solids are incorporated into the vesicles of the granules, in this form the granules contribute an opacifying effect to the paper sheet.
The technique of preparing vesiculated materials from carboxylated, unsaturated polyester resin by emulsifying water into the polyester resin in the presence of a base and then polymerizing the resin is known. A further advance in this technique is the preparation of what is known as "double emulsions~, that is, emulsions wherein the disperse phase is itself an emulsion. For instance U.S. Patent No.
This invention relates to the use of vesiculated polymer granules as a means of providing high opacity in fibrous materials and, more particularly, to compositions comprising said granules ?..,d fibrous cellulosic material of use in papermaking.
The development of fibrous systems having a high opacity has always been a concern to paper manufacturers.
Paper i8 typically made from fibrous cellulosic or non-cellulosic material which may have been delignified and/or bleached, e.g. plant matter, such as trees, cotton, bagasse, and synthetic polymers, such as rayon. To the aqueous fibrous suspension are generally added sizing materials, wet and dry strength additives, defoamers, biocides, dyes, and particularly, retention aids and fillers. The suspension (furnish) is transferred to a forming wire for water drainage to concentrate solids, and subsequently dried to the desired basis weight.
The function of retention aids is to improve the amount of fibrous material, fillers and fines retained by the forming paper sheet, whereas fillers are used to impart suitable optical properties, namely, whiteness, brightness, opacity, and colour.
The degree of opacity of a particular substrate is the result of diffuse light-scattering which occurs when visible radiation is reflected from particles on the surface of the -2- ~L280~i44 substrate and in the substrate medium itself. It has been customary to use high density inorganic mineral fillers, such as calcium carbonate and certain clays, to enhance the opacity of paper sheets. However, the use of such fillers has many disadvantages in the manufacture of paper.
In most cases the use of such inorganic mineral opacifying materials greatly adds to the weight of the paper. This added weight is not desirable with the increasing market demands for production of light-weight paper without loss of opacity.
Also, there is a practical limit to the amount of inorganic mineral filler which can be added to the paper owing to the fact that as the inorganic filler content increases there is a substantial loss of the paper web strength as the tensile strength decreases. This is caused by the interference with the hydrogen bonding between fibrous materials and because with increased inorganic mineral filler content there is less fiber present in the paper sheet to contribute to the strength.
In addition, the generally low retention of the inorganic mineral opacifiers in the paper results in a financial loss by virtue of the by-product waste produced from the wire during sheet formation. More importantly, this poor retention may result in contamination of streams, lakes and other waterways.
Added to the foregoing disadvantages in the use of these inorganic mineral fillers in paper, most inorganic mineral fillers possess a low opacity-to-weight ratio when included in paper.
It is also customary to incorporate in the dilute paper furnish, just before formation on the wire, small amounts of polyelectrolyte retention aids to give improved retention of the inorganic mineral fillers on the wire during sheet formation. For instance, British Patent No. 883l973 ~2~30544 describes the use of trace amounts of a water soluble non-cationic linear vinyl polymer having a molecular weight of at least 5 x 106 and mainly composed of carbamoyl-alkylene linkages containing not more than four carbon atoms, being added to the filler-containing aqueous suspension of cellulose fibers prior to sheet formation, as a retention aid.
Canadian Patent No. 1,046,815 describes a method of manufacturing paper sheet by means of the formation of filler/polymer conglomerates formed by contacting in an aqueous medium a mineral filler with a water soluble polymer having a molecular weight of at least 2 x 106 and possessing a zeta potential of -40 to +40 millivolts.
British Patent No. 1,353,015 describes a method of coating calcium carbonate particles with a selected gellable hydrophilic organic material and thereafter causing the said material to gel so as to form aggregates of gelled hydrophilic material and calcium carbonate particles. Under certain conditions aggregates of a fibrous character may be formed. The use of the coated calcium carbonate filler is stated to give a slightly increased retention without reducing the paper strength.
It has also been suggested that microencapsulated polymers can be incorporated in a paper sheet to enhance opacity. These substantially spherical polymers can be added in the dilute paper furnish before formation on the wire as substitutes for inorganic mineral fillers. These microcapsular opacifiers can also be incorporated in coatings for fibrous or non-fibrous substrates. For example, Canadian Patent No. 856,861 describes polymer granules with a vesiculated structure that can be utilized in a coating composition and polymer films to impart an opacity which is greater than non-vesiculated granules of the same composition.
-4- lZ805~4 u.s. Patent No. 3, 853, 579 and 3, 779, 800 describe a light-weight coating comprising a binder and small colourless plastic, polymeric particles which remain discrete and retain a diameter of about one wave length of visible light. The coating comprising the above mentioned materials may then be applied to a paper substrate in a conventional manner.
U.S. Patent No. 3,816,169 describes a coating of discrete, substantially spherical, air-containing microcapsules having substantially continuous organic, polymeric, solid walls, an average particle diameter of below 2 microns and having pigment particles incorporated in the microcapsular structure. The coating comprising the above mentioned materials may be applied on fibrous and non-fibrous substrates.
It is an object of this invention to provide a means for increasing the opacity of fibrous paper sheets, without significantly increasing the weight of said paper sheet to an extent not heretofore possible.
It i8 another object of this invention to improve the optical property of opacity without decreasing the web strength of a paper compared to a paper made with conventional inorganic mineral fillers.
Still another object of the present invention is to provide a reduction in the amount of opacifier which is lost during the formation of paper on the forming wire.
It is also an object of the present invention to provide a means for increasing the retention of pigmented and/or non-pigmented vesiculated granules.
~hus, it is a primary object of the present invention to provide an aqueous fibrous composition suitable for conversion to a sheet or roll of paper having reduced amounts of opacifying material, particularly pigment.
Accordingly, the invention provides an aqueous composition for use with a fibrous cellulosic or ~280S~A
non-cellulosic material, said composition comprising vesiculated polymer granules and a retention aid; said granules having a mean diameter of 1 to 500 microns, the ratio of the granule diameter to the mean vesicle diameter being at least 5:1, the maximum diameter of the vesicles being 20 microns and the volume of the vesicles being from 5-95~ of the volume of the granules.
By vesiculated polymer granules is meant granules of polymer, preferably spheroidal granules, which have a cell-like structure, the walls of which are provided by the polymer. The granules comprise a plurality of cells or vesicles, that is they are not mono-cellular or balloon-like, and although the vesicles are not necessarily of uniform size, the ratio of the diameter of the granule to the mean individual vesicle diameter is generally at least 5:1. The vesicles typically occupy from 5 to 95% of the total volume of the granules. Low vesicle volumes are usually associated with granules of high mechanical strength which are particularly useful for some applications, but to achieve the most useful opacifying effects the vesicles typically occupy at least 20~ of the total volume of the granules, preferably 20-75% of the volume.
Preferably, each vesicle as hereinbefore described should be enclosed in a continuous shell of polymer. If the granules are produced directly in their required physical size and shape, e.g. by a suspension polymerization process, there will be a random distribution of imperfect vesicles formed therein. On the other hand, if the granules are prepared by, for example, the mechanical degradation of bulk vesiculated polymer, substantially all of the vesicles adjacent to the outer surface of the granules will be imperfect; that is, part of the shell of polymer which preferably encloses them will be broken away.
Although the shape of the granules is not critical in achieving some increase in opacity we have found that spheroidal structure gives the best results.
. , .
-6- ~28054A
The term "retention aid" is a well-known term in the pulp and paper art and means a material that has a coagulating or flocculating effect or an electrochemical interaction on the fibrous material used as the major component of paper to effect increased retention of the fines of the fibrous material, pigment and the like.
Embraced with this term are the three main categories of retention aids, namely, inorganic salts, organic polyelectrolytes of the non-ionic, cationic, anionic and amphoteric types; and natural organic polymers, e.g.
starches and gums. Examples of inorganic salt retention aids are alum and sodium aluminate. Examples of organic polyelectrolytes include polyacrylamides, polyethylene-imines, polyamines, polyamideamines, of high, medium, and low molecular weights. Also, included are quaternized organic polyelectrolytes or natural organic polymers or quaternized non-ionic, cationic, anionic and amphoteric derivatives thereof.
Examples of retention aids of use in the practice of the invention include:
quaternized polyacrylamide (Q-PAM) polydiallyldimethyl ammonium chloride (DAD-MAC) dimethylamine epichlorohydrin (DMA-EPI) ALUM-aluminum sulfate (A12(SO4)3 18H20) Thus, we have now found in accordance with the present invention that polyelectrolyte retention aids have the capability of adhering thereto pigmented and/or non-pigmented vesiculated granules. It is believed that the aforementioned granules are retained in position on the fibers by attractive forces such as electrostatic attraction between the vesiculated granules, fibers and the retention aid by bridging effects. Such conglomerates can be used in the manufacture of paper sheet in order to increase the vesiculated granule content of the sheet. S~rprisingly, it has been found that when these pigmented and/or -7- ~28~54~
non-pigmented vesiculated granules are incorporated into aqueous paper pulp with the polyelectrolyte retention aid added to the furnish before being formed into a paper sheet on the forming wire, the resulting paper sheet achieves an opacity increase heretofore unobtainable.
Thus, in a further feature the invention provides an aqueous composition as hereinbefore defined further comprising a fibrous cellulosic or non-cellulosic material in the form of a paper pulp.
The invention is also of use when inorganic mineral pigment fillers are present in the paper.
The vesiculated granule opacifiers of use in the present invention comprise granules of polymer, essentially spheroidal, which have a cell-like structure, the walls of which are provided by the polymer. This cell-like structure is what is referenced to by the term vesicle. The granules are comprised of many vesicles, that is they are not mono-vesiculated or balloon-like, and although the vesicles are not necessarily of uniform size, the ratio of the diameter of the granule to the mean individual vesicle diameter should be at least S:l. The vesicles should occupy from 5 to 95% of the total volume of the granules. Low vesicle volumes are usually associated with granules of high mechanical strength which are particularly useful for some applications. To achieve the most useful opacifying effects we prefer that the vesicles occupy at least 20% of the total volume of the granules, preferably 20-75% of the volume.
The granules have substantially continuous, solid walls and have a predetermined particle size. Broadly, the granules may have a mean diameter of 1 to 500 microns. In general we find that granules having a mean diameter of 1 to 100 microns are of the most value as opacifying agents.
Preferably, when used as opacifying agents, essentially no granules should exceed the upper dimension limits by more than 20 microns. It is to be understood that the above -8- 1~80S4~
limits may be exceeded by a minor portion of granules which lie outside the stated dimensions.
The term "substantially continuous solid walls", as employed herein, is intended to include solid walled granules which are still sufficiently porous to permit the escape of vaporizable material in gaseous form therethrough upon the application of heat. Ideally each vesicle should be enclosed in a continuous solid wall of tightly cross-linked polymer, but it is not always essential to achieve this. For example, if the granules are produced by an emulsion process, there will be a random distribution of imperfect vesicles formed within the granule. As a further example, if the granules are prepared by the mechanical degradation of bulk vesiculated polymer, it is possible that lS many of the vesicles contiguous with the outer surface of the granule may be imperfect. This may be observed as vesicles with part of the wall of polymer which preferably encloses them broken away.
The vesicles, which are usually spherical in shape, should have a diameter of less than 20 microns and preferably less than 5 microns. The maximum diameter will clepend to a degree on the average diameter of the granule.
We have found that the opacifying effect of the granules tends to increase as the diameter of the individual vesicles decreases. The optimum light scattering effect of vesicles containing air is achieved in the range of 0.2 - O.S micron diameter.
The vesicles may be essentially gaseous; that is, they may be bubbles of air or other gas. In aqueous compositions they may be saturated with vapour, for example, with vapour diffusing into the vesicles, through their polymeric walls from the liquid medium in which the granules are suspended, or may be at least partially filled with liquid taken in from the liquid medium in which the granules are suspended.
When the granules are to be used in a paper sheet, we prefer -9- 1280~44 that most of the liquid in the vesicles be sufficiently volatile to diffuse out of the granules in contact with air.
That is, when the paper sheet has been formed on the wire and is then dried in air, or optionally at an elevated drying temperature, the granules provide essentially gaseous vesicles and in this form contribute an opacifying effect to the paper sheet.
In a further feature of the invention, the vesicles contain particulate solids. The particulate solids may be dispersed therein in a liquid in which the polymer is insoluble or may be associated with essentially gaseous components alone. For example, the particulate solids used in the granules may be any suitable organic or inorganic pigment. Such pigments include those finely divided materials which have been conventionally employed for the purpose of enhancing optical properties, such as opacity, in a paper sheet. Suitable pigments include, for example, Ti02, CaCO3, A12O3 3H2O, barytes (BaSO4), clay, ZnO, ZnS, CaSO3, CaSiO3, talc, and the like. Preferred inorganic pigments for the purpose of the present invention are TiO2, CaCO3, A12O3-3H2O, BaSO4, clay and ZnO, with titanium dioxide being particularly preferred.
Any desired pigment particle size may be used, as long as it i~ suitable for incorporation into the vesicular structure. Thus, for example, titanium dioxide having a mean particle size between 0.1 and 0.35 micron is highly suitable for the purposes of this invention.
The invention is not limited, however, to the use of the above types of pigment and unusual effects may be produced in a paper sheet by the use of granules in which the pigment is at least in part coloured. For example, the pigment may comprise iron oxide, phthalocyanine, quinacridone, cadmium sulphide, or u.v. brighteners.
Chemical or physical tagging agents may be included in the vesicles or in the polymeric cellular material dyes, u.v.
-10- ~8~)S~4 absorbers, u.v. brighteners, fluorescent materials and like additives.
The particulate solids need not be pigments in the generally understood meaning of the term. For example, the particulate solids may be extenders, e.g. bentonite or clays.
The particulate solids may be dispersed in a suitably volatile liquid which subsequently diffuses out of the granules to leave the dry particulate solids therein. We limit the particulate solids concentration for the purposes of this invention to a maximum of 60% by volume of the vesicle and while the size of the chosen particles depends on the actual vesicle diameter, we prefer that the maximum particle diameter should be 1 micron.
It is a particular feature of the present invention that when these particulate solids are incorporated into the vesicles of the granules, in this form the granules contribute an opacifying effect to the paper sheet.
The technique of preparing vesiculated materials from carboxylated, unsaturated polyester resin by emulsifying water into the polyester resin in the presence of a base and then polymerizing the resin is known. A further advance in this technique is the preparation of what is known as "double emulsions~, that is, emulsions wherein the disperse phase is itself an emulsion. For instance U.S. Patent No.
3,255,137 describes the preparation of porous polymeric materials made by dispersing water in a polymerisable liquid, dispersing the resulting emulsion in water and po~ymerising the liquid. U.S. Patent No. 3,822,224 further defines a process of preparing vesiculated polyester resin granules by the dispersion and selection of a styrene solution of carboxylated unsaturatd polyester resin in an aqueous continuous phase in the presence of a selected base.
The process may be refined to a greater degreee by careful selection of both polyester acid value and base type. U.S.
28~)5~
Patent No. 3,879,314 outlines the use of bases which are water-soluble polyamines having at least three amine groups per polyamine molecule and a pKa value of between 8.5 and 10.5.
Although it is not intended to limit the present invention to any particular process of manufacture or choice of carboxylated, unsaturated polyester resins of which the vesiculated beads are comprised, for the purpose of this invention the process of preparation of vesiculated polyester resin granules as outlined in Canadian Patent No.
1,139l048 is preferred.
This process comprises the following listed steps:
1. Preparation of a stable emulsion of water in a polyester solution by emulsification of water into a solution in essentially water-insoluble ~ , ~-ethylenically unsaturated monomer of a carboxylated unsaturated polyester resin. The presence of a base is required to give a stable emulsion of water in the polyester solution.
2. Droplets of emulsion are formed when the emulsion is dispersed into water. A stabiliser is required to be present in the water before disperson of the emulsion.
3. Polymerisation by addition reaction is initiated within the droplets to convert them to cross-linked vesiculatd polyester resin with the following characterization:
(i) the acid value of the polyester is from 5-5Omg.KOH/gm.
(ii) the base is a metal oxide, hydroxide or salt.
Suitable metal cations include, for example, calcium, magnesium, barium, titanium, zinc, lead, strontium and cobalt. Suitable metal salts should have the pKa value of the conjugate acid of the anion greater than 2.
(iii) the amount of base present should be from 0.3 equivalents of metal cation per equivalent of polyester carboxyl group to the quantity required for the complete neutralization of all the carboxyl groups.
-12- ~Z80544 It is also provided that an agueous slurry of stable cross-linked polyester resin vesiculated granules can be prepared by the above mentioned process.
The polyelectrolyte retention aids of use in the S present invention include several materials which have been conventionally employed for wet end addition on a papermaking machine. These materials may include inorganic polyelectrolytes. For example, alum or sodium aluminate;
natural organic polymers, for example, gums, starches, and derivatized starches; synthetic organic polyelectrolytes, for example, polyacrylamide, diallyldimethyl ammonium chloride, polyethyleneimine, amines of epichlorohydrin, and methacryloyloxyethyl trimethyl ammonium methosulfate.
Preferred polyelectrolyte retention aids for the purpose of the present invention are synthetic organic polyelectrolytes with polyacrylamides, diallyldimethyl ammonium chloride and dimethylamine epichlorohydrin being especially preferred.
The ter~ ~polyelectrolyte" as employed herein is intended to include an organic polymer which contains sufficient charged functional groups, or neutral functional groups capable of becoming charged in aqueous solution, to impart water solubility to the poly.ler and to allow it to behave as an electrolyte. Although it is not intended to limit the present invention by any particular theory, it is postulated that the retention aid functions through various complex mechanisms. The modes of operation of retention aids are still theoretical in nature. Mechanisms of function include, for example, filtration or sieving effects, mechanical entrapment of particles, polyelectrolyte adsorption resulting in charge neutralization phenomena and/or particle bridging.
The polyelectrolyte retention aids used in the present invention may also be non-ionic in nature.
The non-ionic polyelectrolytes bear no formal charge but are capable of developing a transient charge in aqueous solutions. This group of retention aids include, for ~L280S~
example, polyalcohols, polyethers, polyamides, poly N-vinyl hetercyclics and polyacrylamides. Preferred polyelectrolyte retention aid of the non-ionic type for the purpose of this invention are polyacrylamides, which may be, for example, homopolymers or copolymers of acrylamide. The molecular weight of these polymers are generally high, i.e. in excess of 1 million. The homopolymers of acrylamide, which are normally essentially non-ionic contain the repeating unit:
-- -( CH2 C ) -I
C = O
I
wherein R may be hydrogen (polyacrylamide) or methyl (polymethylacrylamide).
The polyelectrolyte retention aids used in the present invention may also be anionic, which may contain negatively charged functional groups. This group of retention aids are normally used in an acidic papermaking machine and must contain a positively charged multivalent ion to provide bridging betw~en the high molecular weight anionic polymer and the anionic fibers and fines in the furnish.
This group of anionic retention aids may include, for example, acrylamide/acrylic acid copolymers, and hydrolyzed polyacrylamides. The copolymers of acrylamide and acrylic acid may be represented by the repeating unit:
H2 ICH )m ( CH2 - CH
;:=0 C=O
-14- ~2805~
The carboxylic acid group ICOO ) may be replaced by sulphonic acid (SO3 ) or phosphonic acid (PO3 ), wherein each acid group may be comprised of an ammonium, alkali metal, amine or substituted amine salt of said group. The ratio of m to n may vary to give a weight percent ratio between 100:0 and 50:50 i.e. up to 50 mole ~ of anionic groups may be present in the polymer.
The polyelectrolyte retention aids used in the present invention may be cationic in nature.
Cationic polyelectrolytes contain a positively charged functional group wherein the formal positive charge may reside on, for example, a tri-substituted sulphur known as sulphonium, a tetra-substituted phosphorous (phosphonium) or a tetra-substituted nitrogen (ammonium). Accordingly, suitable cationic polyelectrolytes include, for example, methacryloyloxyethyl trimethyl ammonium methosulphate (METAMS), vinyl benzyl trimethyl ammonium chloride (VBTAC), dimethyldiallyl ammonium chloride (DMDAAC), and 3-acrylamido-3-methyl butyl trimethyl ammonium chloride.
Preferred cationic polyelectrolytes for the purpose of this invention are polymers containing the ammonium group, and polymers containing a quaternary ammonium salt which retains its positive charge in acid, neutral or alkaline papermaking systems being especially preferred.
The use of cationic polymers offers inherent advantages as compared to non-ionic or anionic polymers in most papermaking systems. It is known that the fine solids fraction, materials of less than 75 micron size, of most conventional papermaking systems carry a residual negative charge. Cationic polymers can bond or bridge directly with this fines fraction, eliminating the need for supplemental ions in the system.
The polyelectrolyte retention aids used in the present invention may also be amphoteric, which may be defined as -15- ~Z8054~
polyelectrolytes which contain both positive and negative functional groups in the same polymer chain. The ratio of cationic to anionic functional groups may be such that one is predominant.
The polyelectrolyte retention aids used in the present invention may also be defined according to the mechanism by which the polymer is made. Accordingly, a suitable mechanism of formation may be vinyl addition polymerization which include, for example, acrylamide/acrylic acid copolymers, acrylamide/METAMS copolymers and acrylamide/DMDAAC copolymers. A further example of formation mechanism polymers are condensation polymers, for example, polyethyleneimine and polymers of an amine and epichlorohydrin. For the purpose of the present invention dimethylamine epichlorohydrin is being especially preferred.
The vesiculated polymer granules/polyelectrolyte retention aid conglomerate compositions of this invention can be prepared by continuous or metered addition of an aqueous solution of the polyelectrolyte retention aid, for example, dimethylamine epichlorohydrin to a paper furnish which contains the vesiculated polymer granules, either pigmented, non-pigmented or a blend thereof, and then feed of the resulting material to the wet end of a papermaking machine.
If desired conventional wet-strength agents (such as polymeric resins) or dry-strength agents (such as natural and modified starches and gums) may be present during the formation of the granule/polyelectrolyte polymer conglomerates.
The papermaking process of the invention can be carried out using a conventional furnish formed in part or totally from hardwood, softwood and recycled pulps and/or broke if desired incorporating an internal sizing agent, for example, natural and fortified rosins or an aqueous ketene dimer emulsion.
.. , , ~ ..
16 ~.Z8~
The granule/polyelectrolyte polymer conglomerate compositions of use in accordance with this invention can be employed in an alkaline papermaking system, that is systems in which the paper furnish is maintained at a neutral or alkaline pH value; alternatively, the granule/polyelectrolyte polymer conglomerates may be used in an acid papermaking system, that is systems in which the paper furnish is maintained at an acid pH value.
In yet a further feature the invention provides paper containing dispersed therein vesiculated polymer granules and a retention aid as hereinbefore defined.
The following non-limitative examples illustrate how the invention may be carried into effect.
The following Table lists the materials used in the preparation of 10 microns (95 percentile) diameter maximum 5.2 microns mean average diameter pigmented vesiculated polyester resin granules of use in the practice of the invention.
-17- ~L2aO5~
GROUP MATERIALPARTS (W/W) A water (1) 3.088 surfactant (2) 1.595 antifoam 0.016 B titanium dioxide pigment (3) 10.601 C water 1.029 D polyester (45) 8.686 styrene ~6) 4.8 magnesium oxide` 0.045 E water 1.647 F hydroxy ethyl cellulose (8) poly (vinyl alcohol) solution(l) 0 103 water 30.934 G water 24.701 H cumene hydroperoxide5(90) 0.206 diethylene triamine(11) 0.051 ferrous sulphate 0.003 I bactericide I13) ammonia solution~14) 2 000 (1) A 28% wt. solids ammonium salt of a sulphated alkylphenoxypoly(ethyleneoxy)-ethanol (ex. GAF Corp. Alipal* Co-436) (2) Antifoam Foamaster* NSI (ex Diamond Shamrock~
or Bevaloid* 60 (ex. Imperial Chemical Industries PLC U.K.) (3) Titanium dioxide pigment TiPure* R900 (ex. DuPont) -18- 128~
The process may be refined to a greater degreee by careful selection of both polyester acid value and base type. U.S.
28~)5~
Patent No. 3,879,314 outlines the use of bases which are water-soluble polyamines having at least three amine groups per polyamine molecule and a pKa value of between 8.5 and 10.5.
Although it is not intended to limit the present invention to any particular process of manufacture or choice of carboxylated, unsaturated polyester resins of which the vesiculated beads are comprised, for the purpose of this invention the process of preparation of vesiculated polyester resin granules as outlined in Canadian Patent No.
1,139l048 is preferred.
This process comprises the following listed steps:
1. Preparation of a stable emulsion of water in a polyester solution by emulsification of water into a solution in essentially water-insoluble ~ , ~-ethylenically unsaturated monomer of a carboxylated unsaturated polyester resin. The presence of a base is required to give a stable emulsion of water in the polyester solution.
2. Droplets of emulsion are formed when the emulsion is dispersed into water. A stabiliser is required to be present in the water before disperson of the emulsion.
3. Polymerisation by addition reaction is initiated within the droplets to convert them to cross-linked vesiculatd polyester resin with the following characterization:
(i) the acid value of the polyester is from 5-5Omg.KOH/gm.
(ii) the base is a metal oxide, hydroxide or salt.
Suitable metal cations include, for example, calcium, magnesium, barium, titanium, zinc, lead, strontium and cobalt. Suitable metal salts should have the pKa value of the conjugate acid of the anion greater than 2.
(iii) the amount of base present should be from 0.3 equivalents of metal cation per equivalent of polyester carboxyl group to the quantity required for the complete neutralization of all the carboxyl groups.
-12- ~Z80544 It is also provided that an agueous slurry of stable cross-linked polyester resin vesiculated granules can be prepared by the above mentioned process.
The polyelectrolyte retention aids of use in the S present invention include several materials which have been conventionally employed for wet end addition on a papermaking machine. These materials may include inorganic polyelectrolytes. For example, alum or sodium aluminate;
natural organic polymers, for example, gums, starches, and derivatized starches; synthetic organic polyelectrolytes, for example, polyacrylamide, diallyldimethyl ammonium chloride, polyethyleneimine, amines of epichlorohydrin, and methacryloyloxyethyl trimethyl ammonium methosulfate.
Preferred polyelectrolyte retention aids for the purpose of the present invention are synthetic organic polyelectrolytes with polyacrylamides, diallyldimethyl ammonium chloride and dimethylamine epichlorohydrin being especially preferred.
The ter~ ~polyelectrolyte" as employed herein is intended to include an organic polymer which contains sufficient charged functional groups, or neutral functional groups capable of becoming charged in aqueous solution, to impart water solubility to the poly.ler and to allow it to behave as an electrolyte. Although it is not intended to limit the present invention by any particular theory, it is postulated that the retention aid functions through various complex mechanisms. The modes of operation of retention aids are still theoretical in nature. Mechanisms of function include, for example, filtration or sieving effects, mechanical entrapment of particles, polyelectrolyte adsorption resulting in charge neutralization phenomena and/or particle bridging.
The polyelectrolyte retention aids used in the present invention may also be non-ionic in nature.
The non-ionic polyelectrolytes bear no formal charge but are capable of developing a transient charge in aqueous solutions. This group of retention aids include, for ~L280S~
example, polyalcohols, polyethers, polyamides, poly N-vinyl hetercyclics and polyacrylamides. Preferred polyelectrolyte retention aid of the non-ionic type for the purpose of this invention are polyacrylamides, which may be, for example, homopolymers or copolymers of acrylamide. The molecular weight of these polymers are generally high, i.e. in excess of 1 million. The homopolymers of acrylamide, which are normally essentially non-ionic contain the repeating unit:
-- -( CH2 C ) -I
C = O
I
wherein R may be hydrogen (polyacrylamide) or methyl (polymethylacrylamide).
The polyelectrolyte retention aids used in the present invention may also be anionic, which may contain negatively charged functional groups. This group of retention aids are normally used in an acidic papermaking machine and must contain a positively charged multivalent ion to provide bridging betw~en the high molecular weight anionic polymer and the anionic fibers and fines in the furnish.
This group of anionic retention aids may include, for example, acrylamide/acrylic acid copolymers, and hydrolyzed polyacrylamides. The copolymers of acrylamide and acrylic acid may be represented by the repeating unit:
H2 ICH )m ( CH2 - CH
;:=0 C=O
-14- ~2805~
The carboxylic acid group ICOO ) may be replaced by sulphonic acid (SO3 ) or phosphonic acid (PO3 ), wherein each acid group may be comprised of an ammonium, alkali metal, amine or substituted amine salt of said group. The ratio of m to n may vary to give a weight percent ratio between 100:0 and 50:50 i.e. up to 50 mole ~ of anionic groups may be present in the polymer.
The polyelectrolyte retention aids used in the present invention may be cationic in nature.
Cationic polyelectrolytes contain a positively charged functional group wherein the formal positive charge may reside on, for example, a tri-substituted sulphur known as sulphonium, a tetra-substituted phosphorous (phosphonium) or a tetra-substituted nitrogen (ammonium). Accordingly, suitable cationic polyelectrolytes include, for example, methacryloyloxyethyl trimethyl ammonium methosulphate (METAMS), vinyl benzyl trimethyl ammonium chloride (VBTAC), dimethyldiallyl ammonium chloride (DMDAAC), and 3-acrylamido-3-methyl butyl trimethyl ammonium chloride.
Preferred cationic polyelectrolytes for the purpose of this invention are polymers containing the ammonium group, and polymers containing a quaternary ammonium salt which retains its positive charge in acid, neutral or alkaline papermaking systems being especially preferred.
The use of cationic polymers offers inherent advantages as compared to non-ionic or anionic polymers in most papermaking systems. It is known that the fine solids fraction, materials of less than 75 micron size, of most conventional papermaking systems carry a residual negative charge. Cationic polymers can bond or bridge directly with this fines fraction, eliminating the need for supplemental ions in the system.
The polyelectrolyte retention aids used in the present invention may also be amphoteric, which may be defined as -15- ~Z8054~
polyelectrolytes which contain both positive and negative functional groups in the same polymer chain. The ratio of cationic to anionic functional groups may be such that one is predominant.
The polyelectrolyte retention aids used in the present invention may also be defined according to the mechanism by which the polymer is made. Accordingly, a suitable mechanism of formation may be vinyl addition polymerization which include, for example, acrylamide/acrylic acid copolymers, acrylamide/METAMS copolymers and acrylamide/DMDAAC copolymers. A further example of formation mechanism polymers are condensation polymers, for example, polyethyleneimine and polymers of an amine and epichlorohydrin. For the purpose of the present invention dimethylamine epichlorohydrin is being especially preferred.
The vesiculated polymer granules/polyelectrolyte retention aid conglomerate compositions of this invention can be prepared by continuous or metered addition of an aqueous solution of the polyelectrolyte retention aid, for example, dimethylamine epichlorohydrin to a paper furnish which contains the vesiculated polymer granules, either pigmented, non-pigmented or a blend thereof, and then feed of the resulting material to the wet end of a papermaking machine.
If desired conventional wet-strength agents (such as polymeric resins) or dry-strength agents (such as natural and modified starches and gums) may be present during the formation of the granule/polyelectrolyte polymer conglomerates.
The papermaking process of the invention can be carried out using a conventional furnish formed in part or totally from hardwood, softwood and recycled pulps and/or broke if desired incorporating an internal sizing agent, for example, natural and fortified rosins or an aqueous ketene dimer emulsion.
.. , , ~ ..
16 ~.Z8~
The granule/polyelectrolyte polymer conglomerate compositions of use in accordance with this invention can be employed in an alkaline papermaking system, that is systems in which the paper furnish is maintained at a neutral or alkaline pH value; alternatively, the granule/polyelectrolyte polymer conglomerates may be used in an acid papermaking system, that is systems in which the paper furnish is maintained at an acid pH value.
In yet a further feature the invention provides paper containing dispersed therein vesiculated polymer granules and a retention aid as hereinbefore defined.
The following non-limitative examples illustrate how the invention may be carried into effect.
The following Table lists the materials used in the preparation of 10 microns (95 percentile) diameter maximum 5.2 microns mean average diameter pigmented vesiculated polyester resin granules of use in the practice of the invention.
-17- ~L2aO5~
GROUP MATERIALPARTS (W/W) A water (1) 3.088 surfactant (2) 1.595 antifoam 0.016 B titanium dioxide pigment (3) 10.601 C water 1.029 D polyester (45) 8.686 styrene ~6) 4.8 magnesium oxide` 0.045 E water 1.647 F hydroxy ethyl cellulose (8) poly (vinyl alcohol) solution(l) 0 103 water 30.934 G water 24.701 H cumene hydroperoxide5(90) 0.206 diethylene triamine(11) 0.051 ferrous sulphate 0.003 I bactericide I13) ammonia solution~14) 2 000 (1) A 28% wt. solids ammonium salt of a sulphated alkylphenoxypoly(ethyleneoxy)-ethanol (ex. GAF Corp. Alipal* Co-436) (2) Antifoam Foamaster* NSI (ex Diamond Shamrock~
or Bevaloid* 60 (ex. Imperial Chemical Industries PLC U.K.) (3) Titanium dioxide pigment TiPure* R900 (ex. DuPont) -18- 128~
(4) A 65% weight solids solution of a 3.74/2.34/0.912 (molar) propylene glycol/maleic anydride/phthalic anhydride solution in styrene (5) Styrene (ex. Dow Chemicals) (6) Magnesium oxide Maglite*D (ex. Merck) (7) A 1.5% weight solids aqueous solution of Natrosol*
250HR (ex. Hercules) (8) A 7.5% weight solids aqueous solution of Poval* 224G
250HR (ex. Hercules) (8) A 7.5% weight solids aqueous solution of Poval* 224G
(9) A commercially available 78% weight active ingredients (ex. Pennwalt) (10) Commercially available material (ex. Union Carbide) (11) Commercially available material (ex. J.T. Baker Chemical Co.) (12) Bactericide Proxel* GXL (ex. Imperial Chemical Industries PLC England) (13) A commercially available concentrated 0.9 ammonia solution.
(14) A commercially available thickener Acrysol*
ASE-60 (ex. Rohm & Haas) * Trade Mark 19 ~28~)S44 The pigmented vesiculated polyester resin granules were made as follows:
Materials "A" were mixed and filler "B" added to "A"
with stirring. Stirring was continued at high speed until the filler was completely dispersed, then water "C" was added to give a millbase.
Materials "D~ were mixed until the magnesium oxide was completely dispersed and water "E" was added and emulsified into "D" with high speed mixing.
The millbase was added to this emulsion and similarly emulsified into it until the dispersed particles of the millbase were at least 1 micron in diameter. This is referred to as "the first emulsion".
Materials "F" were blended and the first emulsion added to it under high speed stirring. The stirring was continued until the globules of the first emulsion were 10 micron in diameter. All but one part of water "G" was then added.
This is referred to as "the double emulsionn.
Diethylene triamine and ferrous sulphate of "H" were premixed in 0.5 parts each of water "G" and materials "H"
added to the double emulsion in the order listed above with sufficient stirring to incorporate them. Stirring was then stopped and the mixture was allowed to cure overnight.
Bactericide of "I" was added under stirring, the pH of the mixture adjusted to 8.5-9.5 with the ammonia solution, and the viscosity adjusted to a workable thickness with the thickener.
Further vesiculated polyester resin granules were produced as outlin~d in Examples 2, 3, 4 and 5 of Canadian Patent No. 1,139,048.
Vesiculated polyester resin granules were prepared as outlined hereinabove except that the particle size in the second emulsion was 25 microns (92 percentile) maximum diameter and 12.7 microns mean average diameter.
~ . ' , ., -- . .
-20- ~2 8~ S~ ~
Vesiculated granules were prepared as outlined hereinabove without filler present in the first emulsion stage. The vesiculated granules prepared without filler are hereinafter referred to as "non-pigmented vesiculated granules" to aid in the following commentary when both pigmented and non-pigmented vesiculated granules are in use.
Table A outlines some of the physical parameters obtained when pigmented vesiculated granules are prepared in accordance with the aforementioned methods of preparation for 10 microns (95 percentile~ maximum diameter granules, and 25 microas (92 percentile) ~ _ es.
, TABLE A
Pigmented Vesiculated Granules 10 m 25 m density of dried granules 0.59 g/ml 0.70 g/ml % vesiculation (1)65% 60%
weight solids 21.2~ 23%
volume solids 36% 33~
maximum granule size(2)12 micron 32 microns median granule size5. 2 micron12. 7 microns minimum granule size 3 micron 4 microns vesicle pore size (3) 0.5-3.0 micron 0.5-3.0 micron surface pores on granules<0.2 micron <0.2 micron thickness of granule walls 0.1-0.5 micron 0.1-0.5 micron .
Note:
(1) vesiculation determined by mercury porisimetry (2) granule size determined by Laser Diffraction Granulometer (3) ~nternal diameters measured using Scanning Electron Microscopy The following series of experiments employ the following terms:
Freeness of pulp is a measure of the drainage rate of water through the pulp and is measured in accordance with the TAPPI (Technical Association of the Pulp and Paper Industry) Standard T227 om-75 and is also referred to as Canadian Standard Freeness.
ASE-60 (ex. Rohm & Haas) * Trade Mark 19 ~28~)S44 The pigmented vesiculated polyester resin granules were made as follows:
Materials "A" were mixed and filler "B" added to "A"
with stirring. Stirring was continued at high speed until the filler was completely dispersed, then water "C" was added to give a millbase.
Materials "D~ were mixed until the magnesium oxide was completely dispersed and water "E" was added and emulsified into "D" with high speed mixing.
The millbase was added to this emulsion and similarly emulsified into it until the dispersed particles of the millbase were at least 1 micron in diameter. This is referred to as "the first emulsion".
Materials "F" were blended and the first emulsion added to it under high speed stirring. The stirring was continued until the globules of the first emulsion were 10 micron in diameter. All but one part of water "G" was then added.
This is referred to as "the double emulsionn.
Diethylene triamine and ferrous sulphate of "H" were premixed in 0.5 parts each of water "G" and materials "H"
added to the double emulsion in the order listed above with sufficient stirring to incorporate them. Stirring was then stopped and the mixture was allowed to cure overnight.
Bactericide of "I" was added under stirring, the pH of the mixture adjusted to 8.5-9.5 with the ammonia solution, and the viscosity adjusted to a workable thickness with the thickener.
Further vesiculated polyester resin granules were produced as outlin~d in Examples 2, 3, 4 and 5 of Canadian Patent No. 1,139,048.
Vesiculated polyester resin granules were prepared as outlined hereinabove except that the particle size in the second emulsion was 25 microns (92 percentile) maximum diameter and 12.7 microns mean average diameter.
~ . ' , ., -- . .
-20- ~2 8~ S~ ~
Vesiculated granules were prepared as outlined hereinabove without filler present in the first emulsion stage. The vesiculated granules prepared without filler are hereinafter referred to as "non-pigmented vesiculated granules" to aid in the following commentary when both pigmented and non-pigmented vesiculated granules are in use.
Table A outlines some of the physical parameters obtained when pigmented vesiculated granules are prepared in accordance with the aforementioned methods of preparation for 10 microns (95 percentile~ maximum diameter granules, and 25 microas (92 percentile) ~ _ es.
, TABLE A
Pigmented Vesiculated Granules 10 m 25 m density of dried granules 0.59 g/ml 0.70 g/ml % vesiculation (1)65% 60%
weight solids 21.2~ 23%
volume solids 36% 33~
maximum granule size(2)12 micron 32 microns median granule size5. 2 micron12. 7 microns minimum granule size 3 micron 4 microns vesicle pore size (3) 0.5-3.0 micron 0.5-3.0 micron surface pores on granules<0.2 micron <0.2 micron thickness of granule walls 0.1-0.5 micron 0.1-0.5 micron .
Note:
(1) vesiculation determined by mercury porisimetry (2) granule size determined by Laser Diffraction Granulometer (3) ~nternal diameters measured using Scanning Electron Microscopy The following series of experiments employ the following terms:
Freeness of pulp is a measure of the drainage rate of water through the pulp and is measured in accordance with the TAPPI (Technical Association of the Pulp and Paper Industry) Standard T227 om-75 and is also referred to as Canadian Standard Freeness.
15 Opacity of the paper sheet is expressed as ~ opacity and measured in accordance with CPPA (Canadian Pulp and Paper Association) Standard E-2 using an FMY/C filter for contrast ratio measurements.
-22- ~Z80S~
The term handsheet is used to refer to a paper sheet made in accordance with and employing equipment described in the TAPPI standard T205 om-81.
Conditioning refers to the conditioning atmosphere of 23.0+1.0 degrees Centigrade and 50.0~2.0 percent relative humidity that the paper sheets are exposed to in accordance with TAPPI standard T405 om-83 Handsheets were prepared by the following general procedure.
The furnish or solids in the pulp slurry comprised 100 percent by weight of fully bleached chemical hardwood pulp.
The pulp was a commercially produced kraft pulp, and was subsequently beaten to a Canadian Standard Freeness of 325 ml. After beating, individual samples of pulp were disintegrated, stirred, and varied amounts of fillers and retention aids added. The pH was adjusted for either acid, neutral, or alkaline conditions to simulate industrial headbox conditions. The furnish was subsequently passed through a sheetmaker and the resultant handsheet pressed and conditioned.
The following series of experiments were performed.
All series except Series D involved four commercially available retention aids.
Series A were performed with a furnish comprising a hardwood pulp.
Series B were performed with a furnish comprising a hardwood pulp, and a filler of anatase titanium dioxide.
Series C were performed with a furnish comprising a hardwood pulp, and a filler of vesiculated polymeric granules of median particle size 5 microns.
Series D were performed with a furnish comprising a hardwood pulp, and a filler comprising vesiculated polymeric granules of median particle size of 5 microns.
Series E were performed with a furnish comprising a hardwood pulp, and a filler of pigmented (rutile titanium -23- lZ8054~
dioxide) vesiculated polymeric granules of median particle size 5 microns.
Series F were performed with a furnish comprising a hardwood pulp, and a filler comprisin`g pigmented (rutile titanium dioxide) vesiculated polymeric granules of median particle size 5 microns and anatase titanium dioxide.
Series G were performed with a furnish comprising a hardwood pulp, and a filler comprising pigmented (rutile titanium dioxide) vesiculated polymeric granules and non-pigmented vesiculatd polymeric granules both of median particle size of 5 microns.
Series H were performed with a furnish comprising a hardwood pulp, and a filler of pigmented vesiculated polymeric granules of median particle size of 12 microns.
Series I were performed with a furnish comprising a hardwood pulp, and a filler comprising pigmented (rutile titanium dioxide) vesiculated polymeric granules of median particle size 12 microns and rutile titanium dioxide.
Series J were performed with a furnish comprising a hardwood pulp, and a filler comprising pigmented (rutile titanium dioxide) vesiculated polymeric granules of median particle size 12 microns and non-pigmented vesiculated polymeric granules of median particle size of 5 microns.
EXAMPLE 1 - (Series A) The hereinabove general procedure for the preparation of furnishes was carried out to prepare furnish comprising fully bleached chemical hardwood kraft pulp and further comprising four, separate samples of various commercially available retention aids.
Sample 1 retention aid was added as a 1 volume percent solution of a low molecular weight, high activity, liquid cationic quaternized polyacrylamide (Q-PAM). The addition level was 4 pounds per ton of pulp oven-dried weight.
-24- lZ805~'~
Sample 2 retention aid was added as a 1 volume percent solution of a moderate molecular weight, polycationic polymer of diallyldimethyl ammonium chloride (DAD-~AC). The addition level was 4 pounds per ton of pulp oven-dried weight.
Sample 3 retention aid was added as a 1 volume percent solution of a highly charged moderate molecular weight cationic polymer of dimethylamine epichlorohydrin (DMA-EPI).
The addition level was 4 pounds per ton of pulp oven-dried weight.
Sample 4 retention aid was a 1 weight percent solution of Alum (aluminum sulphate A12(SO4)3 18H20) in de-ionized water. The addition level was 2 weight percent on pulp oven dried weight.
The furnish containing 0.8 dry weight percent of fully bleached chemical hardwood kraft pulp at a Canadian Standard freeness of 325 milliliters in 2 liters of de-ionized water was disintegrated for 5 minutes. The furnish was then placed under a mixer. Eight samples were prepared in an identical manner.
The first run was adjusted to pH 4.5 with dilute sulphuric acid. Runs 2 to 5 inclusive contained one of the retention aids, and the pH adjusted to 4.5 with dilute sulphuric acid. Runs 6 to 8 inclusive were adjusted to various pHs with either dilute sulphuric acid or dilute sodium hydroxide.
Results are shown in Table 1. - ______ ____, ~28C)5~ll ~ ~ o ~I , dP
~ ~ ~ u) O
~ R
:, I ~ 1 1 0 ,, D
a ~S
. ~
-26- l2aos~
EXAMPLE 2 - (Series B) Runs 9 to 26 inclusive were prepared as in the above mentioned general procedure. The furnish preparation and retention aids used were as those described in Example 1, except a filler (anatase titanium dioxide) was added. The anatase titanium dioxide was added as an aqueous mill base prepared by high shear dispersion of a slurry comprising 70 weight percent Tioxide A-HR anatase titanium dioxide; 4.2 weight percent of a 3.3 weight percent solution of tetra-sodium pyrophosphate (TSPP-Na4P207 10 H20), and 2.8 weight percent of de-ionized water.
The components in the furnish were added in the following order: pulp, filler,~retention aid, then either dilute sulphuric acid or dilute sodium hydroxide as required for pH adjustment.
The filler level was evaluated at two additional levels. The first level was 5 weight percent of filler on the oven dry weight of the pulp in the furnish and the second level was 10 weight percent of filler on the oven dry we,ight of the pulp in the furnish.
The results are shown in Table 2. ", C
~28054'~ C- I-L 711 _ _ _ O ~ r-- ~--1 ~1 1~ ~I N ~ 1~-& ~ ~ ~ ~ u~ c~ ~ o ~ o ~ r- ~r ~ ~ er 0~
, .
~ I l ~ ¦ N l l l l ~3 ~ ~ I I I I I I I I I ~
m ~ ~ I I I I I I I I ~r I I I I I I I I I
~r; ~ .
~ ~ I IIIII~rIIIIIIIIII
P;
u~ ~ u~
O ~ . ~ l l l l l l l l l l l l l l l l l l ~ ~
L P~ ~ ~ l l l l l l l l l l l l l l l l l l m ~
E~ ~ O m : ,~ ::: c: ~: : ~:
_ ~ ~ ~ = . = . . C : .
+
i~ o ~ N ,~ ~ O _~ N ~ ~ N ~`I
1280~
EXAMPLE 3 -- (Series C) Runs 27 to 39 inclusive were prepared as in the above mentioned general procedure. The furnish preparation and retention aids used were as those described in Example 2 except the filler used was vesiculated polymeric granules.
The vesiculated polymeric granules were used in the emulsion form as prepared and described in the foregoing text. The order of addition of the furnish components, and the filler levels used are as those described in Example 2.
Runs 27, 28, and 29 demonstrate the % opacity contributed to the pulp furnish by the vesiculated polymeric granules in the absence of a retention aid. Runs 30 to 32, 34, 36 to 39 inclusive demonstrate the % opacity contributed to the pulp furnish by the vesiculted polymeric granules in the presence of one of the retention aids as described in Example 1. Runs 28, 33 and 35 demonstrate the effect of altering pH.
The results are shown in Table 3.
--29- ~L2805~L~
r o~ r o~ 0 ~ ~ er ~ ~ ~ ~ o u ~ ~ ~ ~ Lr~ r ~ 0 n a~ In 0~o _ ~I) ~ l l l l l l I ~ N I ¦ ¦ t~
~ ~ l l l l l l l l l l O ~¢ Z:i I I I I I ~r ~ I I I I ~ I
U~ ,0 ~ ~ 3 I I I I r H p:;
~; ~ I I I ~ I I I I I ~ I I I
U~ _ _ ~ l ll l l l l l l l l l l .
:5 ~ dP dP dP doP
r~ ~ U~
~C ~
~ ~ U~ : dP
~ 0 ~ 0 ~ ~
+~
r~ o r~
'~ 2805~4 EXAMPLE 4 - (Series D) Runs 40 and 41 were prepared as in the above mentioned general procedure. The furnish preparation and order of material addition were as those described in Example 2 except that the filler used was a 1:1 weight ratio blend of vesiculated polymeric granules and anatase titanium dioxide.
No retention aids were used in this Example.
The results are shown in Table 4, also included are runs 27 and 29 of Series C, and runs 9 and 11 from Series B
10 for ease of comparison of results. ~
1~8~5~Z~
~ OD
& t~
. ~P
_ ~ ~,. = =
o ~L I O I 1_, , ~: ~ I l l l l I
' ~_" ~
~N Ul t ~ ,, t U, t ~ ~ I dP * , o dP
~ u~ ~ I _l In ~¦ a~ ~ ' _ ~ e .
a~
æ 0 0 g ~ ~ ~
~-a ~ 0 o~ ~ 0 . ~ (~ ~ ~ ~ N ~ ~ ~ Q, ,~ n ~ O
h ~ E~ ~ ~ ~ E~ P. ~4 ~ ~ E~
r~ I~ O
o~
. , ~Z8~5 EXAMPLE 5 - (Series E) Runs 40 to 58 inclusive were prepared as in the aforementioned general procedure. The furnish preparation, retention aids used, and order of material addition were as those described in Example 2 excepting that the filler used was pigmented (rutile titanium dioxide) vesiculated polymeric granules. The granules used were in the emulsion form as prepared and described in the foregoing text. The filler levels were 5 and 10 weight percent on pulp weight.
The results are shown in Table 5, also included are runs 9, 11 and 22 from Table 2 for ease of comparison of -33- :~LZ80544 C-I-L 711 ~ u~ r o er o~ ~ ~o ~
H Ul ~ ~ ~~ D ~ ~ O O ~9 ~r ~D 11~ ~ IJ~ O el~
~ ............ ~
O r 1` ~ r` 1` t~ 1` 1~ 1` r- r` o~ 1` 1` 1` GO 0~ 0~ OD r`
d~ _ .
~ ~ I I I I I I I I I I I I I I I I I
O ~ I I I I I I I I I I I I I I ~ I I I I
O H
O
IIIIIIIlerlIIIIIIIOO
~;
~ IIOIOOOO~rOOIIOIIOIII
U~
~ 0~ I dP t 1 ,, 1 1 1 1 1 1, O O O O O, O u~
E~
-~.q ~ g~ IIIOIIIIIIIIIIIIIIII
O ~ d~ dP dP
n _~ ~ d~ 1 dP
~ U~=: _1:::: ~:::::: _1:::
~ ¦ ~ N ¦
. ~
~ ~ ~ ~ ~ ~i In ~ I` 0~ a~ o ~
, ~L2a~5~
EXAMPLE 6 - tSeries F) Runs 59 to 65 inclusive were prepared as in the foregoing general procedure. The furnish preparation, retention aids used, and order of material addition were as those described in Example 2 excepting that the filler used was a 1:1 weight ratio blend of pigmented (rutile titanium dioxide) vesiculated polymeric granules and anatase titanium dioxide. The granules used were in the emulsion form as described in the foregoing text. The anatase titanium dioxide was used as a mill base disperson as described in Example 2. The filler levels were 5 and 10 weight percent on pulp weight.
The results are shown in Table 6, also included are runs 9 and 11 from Table 2 and runs 42 and 44 from Table 5 for ease of comparison of results.
1 280~;4f~ C-I--L 71. ~
u~ D O In D
n o ~
~r ~ ~r~ c~ ~ ~ ~ r-& I`
, ~ U~
d' Q) ~ l l l l l l l l l l u) ~ II I I I I I I N
O H
a .~ ~ t ~I t I I I t o . _ ~ ~
a) ~ l ll l l l l l l l ~ ~ I II I II I ~r I I I
~; _.~
~q ~ l l l l l l l l l l rLl ~ I I I I I I ~ I I I I
H _ dP
~; ~ oP I ~ O I d~ ~
~ .~ u~
U~
:~ ~1 I I I I I I I I t I t .
o ~
10 dP ~ -I ~ dP dP
_l ~ :~ I u~
~ ~ ,.
o'P O O d~
u~ , E~
~ '~a ~ Eo~ V,~ E EE,::::
u~ ~a~ a~ ~+
I .,, + O + + + ~ + . ~ .
. ~ ~ ~ U~
~ . ~ O
~8~5~4 EXAMPLE 7 - (Series G) Runs 66 to 75 inclusive evaluated a hardwood furnish with a filler comprising a blend of pigmented (rutile titanium dioxide) vesiculated polymeric granules and non-pigmented vesiculated polymeric granules with and without retention aids. These eleven runs were prepared as in the foregoing general procedure. The furnish preparation, retention aid use, and order of material addition were as those described in Example 2 except that the filler used was a 1:1 weight ratio of pigmented vesiculated polymeric granules and non-pigmented vesiculated polymeric granules.
The results are shown in Table 7, also included are runs 27, 29, 32, and 38 from Table 3 and runs 42, 44, 50 and 15 55 for ease of comparison of results. ~
-~7- ~Z8~)5~ C-I-L 711 ~ ~ ~ ~ I~ ~ o ~ o U~ o . . . ~
_ ~ ~ l l l l l l l l l l l I
O ~
.~ ~ I l I I I I I I I~
o ~ _ .
~ ~ b l l l 1 1 ~ ~; ... . . .
H ~1 1/1 --~
u~ I ~ _~ I In ~: : : In I
. ... _ /Y .~ ~ ~ I
~ . _ ~ : : : _ U~:::::
~ g)~ 'g .__ ~' I` ~ 0 ~ o ~ i o ~r ~D ~ ~r ~D ~D ~D 1` 1` ~ .n . _ __ . _. .
3~ 1 ~8~)S4~ C-I-L 711 . _ ~ o ~
5~ o~
~ oo o ~
.~. , n o~
_ I ~ I I
o _ ~:
:~ ~ ~
H ~
E~ ~
U~ ~ l l l l l I
E'~
* dP ~
1~ 1~ I
O ~
~ ~ ~ ~* ~
C ~ ~ I : : _ :
~ i!~
,~'+
_ :~ ~ r ~
. . .
~280S4at EXAMPLE 8 -- (Series H) Runs 76 to 86 inclusive evaluated a hardwood furnish with a filler comprising a pigmented (rutile titanium dioxide) vesiculated polymeric granule with a median diameter of 12 microns, with and without retention aids.
These eleven runs were made as in the foregoing general procedure. The furnish preparation, retention aids used and the order of material addition were as those described in Example 2 except that the filler was an emulsion form of the pigmented vesiculated polymeric granules.
The results are shown in Table 8. -- - 4 - 1280544 c- -I. 7 1 1 H ~ I` ~ ~ ~10 C1~ 00 0 ~ l & ~ x ~r x er _ ~
o ~ I I 1 1,1 1 1 1~1 1 a .~ ~ ~ r :C o ~
~ ~ I I I 1 1~1 1 1 1 1 o~
~ ~ I I I lerl I I I I I
.~ ~ I I I I I I I I I I I
_ t ~ ~ I I I I I I I I I I I
CO ~
~ o 3~ dP
m ~
~ ~ ~ , i ~:: ::
+ ~.
g~ : : : : : : : : : :
~D oo a` X -i CC~ cO OD C~ 0 ~Z80S4~
EXPERIMENT 9 -- (series I) Runs 87 to 94 inclusive were performed with a hardwood pulp, filler comprising pigmented (rutile titanium dioxide~
vesiculated polymeric granules of median particle size 12 microns and non-pigmented vesiculated polymeric granules of median particle size of 5 microns, and retention aids.
These eight runs were made as in the foregoing general procedure. The furnish preparation, retention aids used, and the order of material addition were as the method described in Example 2 except for the filler composition which was an emulsion form of the pigmented and non-pigmented vesiculated granules.
The results are shown in Table 9 including runs 76 and 78 from Table 8 and runs 9 and 11 from Table 2 for ease of comparison.
-42- 1 ~8054~1 C-I-I. 7~ I
~; 1~ N ~ r ~ o q ~) o tY~ ~I N N U~ _I ~) d ' ~: ~ ~ ~ u~ In ~ ~ O~ 0~ 0 r o dO I . _ _ . o ~ l I I I I I I 1_1 1 ~ ~ I I I I I I I I I ~
c H~) ~ 1 7 1 I I I I I ~
~ _ u7 ~ I I I I I I I ~ I I I I _ E l N ¦ ~ : : N IJ I
U~ ~ ~
~ ~ l l l l l l l l l l l I
,1 C ~
O ~'-~_I ~ ~ ~d N It~ I Ltl: N 11~
~ l i m ~ dP ~ N _1 111 I
~t I ~ I
I -~ I` ~ a~ co oo o' _~ ~
- . . .
~ 280544 EXPERIMENT 10 - (Series J) Runs 95 to 102 inclusive were performed with a hardwood pulp, filler comprising a blend of pigmented (rutile titanium dioxide) vesiculated polymeric granules of median 5 particle size diameter of 12 microns and non-pigmented vesiculated polymeric granules of median particle size of 5 microns, with and without the use of retention aids. These eight runs were prepared as in the foregoing general procedure. The furnish preparation, retention aid used, and 10 order of material addition were as those described in Example 2 except that the filler used was a 1:1 weight ratio blend of the pigmented and non-pigmented vesiculated polymeric granule emulsions.
The results are shown in Table 10 including runs 76 and 15 78 from Table 8, runs 27 and 29 from Table 3 for ease of comparison of results.
44- ~280~;44 C-I-L 711 cn Ln o~ r~ ~ o ~ ~D Ln o o~ n Ln ~ u~
~r Ll~ ~ n .n ~r ~D Ln ~ Ln o & ~ ~
_ ~
~ Ln 2 = ~ 2 ~ 2 ~ F~ I I I I I ~ I I I 1~1 ~ ~ I I I I I I I I I~
v r~ ~
~; ~ I I I I I I I I er I I I
H _ ~ I I t l I I I ~
t~n ~ ~1 11 111 11111 ~ ~ 1~ H ~`~ I Ln I I ~ : : Ln o ~
, l~g 1~ , ~ LdnP I n ,~ I ~: : : LdnP
~ ~ i ._ _ i e ~ dP dnP :: ,~:: n::: _l . ~ ~ l j w ~D g ~ ~ g ~ ~
g , ~
I . . .
Ln LD ~ 0 ~n o o o , ~Z80~;44 Discussion of Tabulated Results It can be seen from Table 1 - (Series A) that the use of retention aids in combination with the fully bleached S chemical hardwood kraft pulp, does not contribute to any significant change in percent opacity. Thus, any gains in opacity reported in the following series can be directly attributed to interactions between the fillers, retention aids and pulp. The decrease in opacity observed in furnishes adjusted to neutral or alkaline conditions may be attributed to small repulsive forces increasing as the level of free negatively charged hydroxide ions was increased. In the furnish, which is already anionic in nature, these forces may decrease retention of the pulp flocs.
It can be seen from Table 2 (Series B) that at the 5%
filler level the maximum percent opacity obtained was with the use of Alum as a retention aid (79.47%). It can also be seen that pulp with anatase titanium dioxide, in the absence of a retention aid, shows no significant change in % opacity as the pH changes from acid to alkaline. The presence of retention aids renders the pulp plus anatase titanium dioxide furnish slightly more sensitive to changes in pH
when observing % opacity. The degree of difference is still quit,e small.
It can be seen from Table 3 (Series C) that at the 5%
filler level the maximum percent opacity obtained was with the use of the retention aid dimethylamine epichlorohydrin (76.87). A further gain of 0.8% opacity was obtained when the pH was increased from 4.5 to 8.5. At the 10% filler level the maximum percent opacity was also obtained with the use of the retention aid dimethylamine epichlorohydrin (79.27).
It can also be seen from Table 3 that when the pH of pulp with vesiculated granules was raised from 4.5 to 8.5 a small decrease in % opacity was observed when the pH was ~Z80S44 raised in the furnish which contains the dimethylamine epichlorohydrin, pulp, and vesiculated granules (runs 32 and 33) an increase % opacity was observed. Run number 35 which demonstrated the effect of alkaline pH on a furnish containing Alum was included as a known control. It is known in the papermaking field that Alum is useful only in acidic papermaking due to its chemical structure and ionic nature. Run 35 demonstrated the expected drop in opacity of Alum used in an alkaline furnish.
It can be seen from Table 4 - (Series D) that when vesiculated polymeric granules and anatase titanium dïoxide were combined to form a filler at acidic pH, an enhancement of % opacity could be gained over the use of anatase titanium dioxide alone as a filler. This feature was observed for both 5 and 10 percent filler level on pulp.
It can be seen from Table 5 - (Series E) that % opacity gains of a significant amount were obtained with the use of pigmented vesiculated polymeric granules over anatase titanium dioxide. Comparing the two fillers without the use of retention aids at the 5% filler level on pulp (runs 42 and 9) a gain of 0.7 percent opacity was achieved. At the 10 percent filler level on pulp (runs 44 and 11) a gain of 0.4 percent opacity was achieved. With the use of retention aids comparing 5 percent filler level on pulp, the anatase titanium dioxide sample using Alum achieved 79.5 percent opacity. This was compared to pigmented vesiculated polymeric granules with dimethylamine epichlorohydrin as the retention aid which achieved an opacity of 79.0 percent at pH 4.5 or 81.04 percent at pH 6.5.
When the level of pigmented vesiculated polymeric granules was increased to 10 percent on pulp weight and incorporated the use of dimethylamine epichlorohydrin as the retention aid an excellent opacity of 82.6 percent at pH 4.5 and 84.5 percent at pH 7.5 was achieved. This reflects a gain of 10 percent opacity units over the use of pigmented ~.280544 vesiculated polymeric granules without the use of a retention aid. This example illustrates the claims of this invention.
It can be seen from Table 6 (Series F) that the maximum percent opacity obtained in this Series (which is examining the effect of combining titanium dioxide and pigmented vesiculated granules together as a filler) was obtained when the blend was used at a level of 10 percent on pulp weight and incorporated the retention aid dimethylamine epichlorohydrin (81.20~ opacity). Runs 9, 42 and 59 show that at a 5% combined filler level the use of the pigmented granules was better for percent opacity than titanium dioxide alone. The blend of the two fillers gave a percent opacity value that was between that for the fillers separately. This effect was noticed at 5 and 10 percent filler levels.
The excellent response of the filler blend to all four retention aids demonstrated that where a particular retention aid would enhance opacity for one of the fillers, this enhancement was also observed in the blend of fillers.
It can be seen from Table 7 (Series G) that if the filler comprises a blend of both pigmented and non-pigmented vesiculated granules the percent opacity achieved was generally higher than for non-pigmented vesiculated polymeric granules as a single filler and slightly lower than pigmented vesiculated polymeric granules as a single filler. With the use of retention aids the blend of non-pigmented and pigmented vesiculated polymeric granules achieved percent opacities almost equal to the pigmented granules. This could mean that a paper sheet prepared with a properly tailored blend of pigmented and non-pigmented vesiculated granules could achieve a target percent opacity and have a corresponding reduction in weight and cost of the paper sheet.
.
~Z80544 It can be seen from Table 8 (Series H) that the larger median diameter (12 microns) pigmented vesiculated granules have an improved ~ opacity gain over anatase titanium dioxide and 5 micron diameter (median) pigmented vesiculated granules when used as a filler. The retention aid dimethylamine epichlorohydrin assisted in increasing the percent opacity gain.
It can be seen from Table 9 (Series I) that the blending of pigmented vesiculated polymeric granules (median diameter 12 microns) and anatase titanium dioxide to form a filler, did not give a significant increase in percent opacity over the use of the granules alone. The best retention aids for increased percent opacity were again noted to be dimethylamine epichlorohydrin and alum. Each retention aid contributing to the filler portion best suited to its structure, the DMA-EPI was definitely aiding the granules, and alum aiding the Tio2.
It can be seen from Table 10 (Series J) that the blend of larger median diameter (25 microns) pigmented vesiculated granules with non-pigmented vesiculated granules as a filler for a paper sheet achieved better percent opacity than by using non-pigmented granules only. The excellent increase in percent opacity obtained with the use of the retention aid dimethylamine epichlorohydrin could suggest that a paper sheet prepared with a properly tailored blend of pigmented and non-pigmented vesiculated polymeric granules could achieve a targeted percent opacity and have a corresponding reduction in weight and cost of the paper sheet.
-
-22- ~Z80S~
The term handsheet is used to refer to a paper sheet made in accordance with and employing equipment described in the TAPPI standard T205 om-81.
Conditioning refers to the conditioning atmosphere of 23.0+1.0 degrees Centigrade and 50.0~2.0 percent relative humidity that the paper sheets are exposed to in accordance with TAPPI standard T405 om-83 Handsheets were prepared by the following general procedure.
The furnish or solids in the pulp slurry comprised 100 percent by weight of fully bleached chemical hardwood pulp.
The pulp was a commercially produced kraft pulp, and was subsequently beaten to a Canadian Standard Freeness of 325 ml. After beating, individual samples of pulp were disintegrated, stirred, and varied amounts of fillers and retention aids added. The pH was adjusted for either acid, neutral, or alkaline conditions to simulate industrial headbox conditions. The furnish was subsequently passed through a sheetmaker and the resultant handsheet pressed and conditioned.
The following series of experiments were performed.
All series except Series D involved four commercially available retention aids.
Series A were performed with a furnish comprising a hardwood pulp.
Series B were performed with a furnish comprising a hardwood pulp, and a filler of anatase titanium dioxide.
Series C were performed with a furnish comprising a hardwood pulp, and a filler of vesiculated polymeric granules of median particle size 5 microns.
Series D were performed with a furnish comprising a hardwood pulp, and a filler comprising vesiculated polymeric granules of median particle size of 5 microns.
Series E were performed with a furnish comprising a hardwood pulp, and a filler of pigmented (rutile titanium -23- lZ8054~
dioxide) vesiculated polymeric granules of median particle size 5 microns.
Series F were performed with a furnish comprising a hardwood pulp, and a filler comprisin`g pigmented (rutile titanium dioxide) vesiculated polymeric granules of median particle size 5 microns and anatase titanium dioxide.
Series G were performed with a furnish comprising a hardwood pulp, and a filler comprising pigmented (rutile titanium dioxide) vesiculated polymeric granules and non-pigmented vesiculatd polymeric granules both of median particle size of 5 microns.
Series H were performed with a furnish comprising a hardwood pulp, and a filler of pigmented vesiculated polymeric granules of median particle size of 12 microns.
Series I were performed with a furnish comprising a hardwood pulp, and a filler comprising pigmented (rutile titanium dioxide) vesiculated polymeric granules of median particle size 12 microns and rutile titanium dioxide.
Series J were performed with a furnish comprising a hardwood pulp, and a filler comprising pigmented (rutile titanium dioxide) vesiculated polymeric granules of median particle size 12 microns and non-pigmented vesiculated polymeric granules of median particle size of 5 microns.
EXAMPLE 1 - (Series A) The hereinabove general procedure for the preparation of furnishes was carried out to prepare furnish comprising fully bleached chemical hardwood kraft pulp and further comprising four, separate samples of various commercially available retention aids.
Sample 1 retention aid was added as a 1 volume percent solution of a low molecular weight, high activity, liquid cationic quaternized polyacrylamide (Q-PAM). The addition level was 4 pounds per ton of pulp oven-dried weight.
-24- lZ805~'~
Sample 2 retention aid was added as a 1 volume percent solution of a moderate molecular weight, polycationic polymer of diallyldimethyl ammonium chloride (DAD-~AC). The addition level was 4 pounds per ton of pulp oven-dried weight.
Sample 3 retention aid was added as a 1 volume percent solution of a highly charged moderate molecular weight cationic polymer of dimethylamine epichlorohydrin (DMA-EPI).
The addition level was 4 pounds per ton of pulp oven-dried weight.
Sample 4 retention aid was a 1 weight percent solution of Alum (aluminum sulphate A12(SO4)3 18H20) in de-ionized water. The addition level was 2 weight percent on pulp oven dried weight.
The furnish containing 0.8 dry weight percent of fully bleached chemical hardwood kraft pulp at a Canadian Standard freeness of 325 milliliters in 2 liters of de-ionized water was disintegrated for 5 minutes. The furnish was then placed under a mixer. Eight samples were prepared in an identical manner.
The first run was adjusted to pH 4.5 with dilute sulphuric acid. Runs 2 to 5 inclusive contained one of the retention aids, and the pH adjusted to 4.5 with dilute sulphuric acid. Runs 6 to 8 inclusive were adjusted to various pHs with either dilute sulphuric acid or dilute sodium hydroxide.
Results are shown in Table 1. - ______ ____, ~28C)5~ll ~ ~ o ~I , dP
~ ~ ~ u) O
~ R
:, I ~ 1 1 0 ,, D
a ~S
. ~
-26- l2aos~
EXAMPLE 2 - (Series B) Runs 9 to 26 inclusive were prepared as in the above mentioned general procedure. The furnish preparation and retention aids used were as those described in Example 1, except a filler (anatase titanium dioxide) was added. The anatase titanium dioxide was added as an aqueous mill base prepared by high shear dispersion of a slurry comprising 70 weight percent Tioxide A-HR anatase titanium dioxide; 4.2 weight percent of a 3.3 weight percent solution of tetra-sodium pyrophosphate (TSPP-Na4P207 10 H20), and 2.8 weight percent of de-ionized water.
The components in the furnish were added in the following order: pulp, filler,~retention aid, then either dilute sulphuric acid or dilute sodium hydroxide as required for pH adjustment.
The filler level was evaluated at two additional levels. The first level was 5 weight percent of filler on the oven dry weight of the pulp in the furnish and the second level was 10 weight percent of filler on the oven dry we,ight of the pulp in the furnish.
The results are shown in Table 2. ", C
~28054'~ C- I-L 711 _ _ _ O ~ r-- ~--1 ~1 1~ ~I N ~ 1~-& ~ ~ ~ ~ u~ c~ ~ o ~ o ~ r- ~r ~ ~ er 0~
, .
~ I l ~ ¦ N l l l l ~3 ~ ~ I I I I I I I I I ~
m ~ ~ I I I I I I I I ~r I I I I I I I I I
~r; ~ .
~ ~ I IIIII~rIIIIIIIIII
P;
u~ ~ u~
O ~ . ~ l l l l l l l l l l l l l l l l l l ~ ~
L P~ ~ ~ l l l l l l l l l l l l l l l l l l m ~
E~ ~ O m : ,~ ::: c: ~: : ~:
_ ~ ~ ~ = . = . . C : .
+
i~ o ~ N ,~ ~ O _~ N ~ ~ N ~`I
1280~
EXAMPLE 3 -- (Series C) Runs 27 to 39 inclusive were prepared as in the above mentioned general procedure. The furnish preparation and retention aids used were as those described in Example 2 except the filler used was vesiculated polymeric granules.
The vesiculated polymeric granules were used in the emulsion form as prepared and described in the foregoing text. The order of addition of the furnish components, and the filler levels used are as those described in Example 2.
Runs 27, 28, and 29 demonstrate the % opacity contributed to the pulp furnish by the vesiculated polymeric granules in the absence of a retention aid. Runs 30 to 32, 34, 36 to 39 inclusive demonstrate the % opacity contributed to the pulp furnish by the vesiculted polymeric granules in the presence of one of the retention aids as described in Example 1. Runs 28, 33 and 35 demonstrate the effect of altering pH.
The results are shown in Table 3.
--29- ~L2805~L~
r o~ r o~ 0 ~ ~ er ~ ~ ~ ~ o u ~ ~ ~ ~ Lr~ r ~ 0 n a~ In 0~o _ ~I) ~ l l l l l l I ~ N I ¦ ¦ t~
~ ~ l l l l l l l l l l O ~¢ Z:i I I I I I ~r ~ I I I I ~ I
U~ ,0 ~ ~ 3 I I I I r H p:;
~; ~ I I I ~ I I I I I ~ I I I
U~ _ _ ~ l ll l l l l l l l l l l .
:5 ~ dP dP dP doP
r~ ~ U~
~C ~
~ ~ U~ : dP
~ 0 ~ 0 ~ ~
+~
r~ o r~
'~ 2805~4 EXAMPLE 4 - (Series D) Runs 40 and 41 were prepared as in the above mentioned general procedure. The furnish preparation and order of material addition were as those described in Example 2 except that the filler used was a 1:1 weight ratio blend of vesiculated polymeric granules and anatase titanium dioxide.
No retention aids were used in this Example.
The results are shown in Table 4, also included are runs 27 and 29 of Series C, and runs 9 and 11 from Series B
10 for ease of comparison of results. ~
1~8~5~Z~
~ OD
& t~
. ~P
_ ~ ~,. = =
o ~L I O I 1_, , ~: ~ I l l l l I
' ~_" ~
~N Ul t ~ ,, t U, t ~ ~ I dP * , o dP
~ u~ ~ I _l In ~¦ a~ ~ ' _ ~ e .
a~
æ 0 0 g ~ ~ ~
~-a ~ 0 o~ ~ 0 . ~ (~ ~ ~ ~ N ~ ~ ~ Q, ,~ n ~ O
h ~ E~ ~ ~ ~ E~ P. ~4 ~ ~ E~
r~ I~ O
o~
. , ~Z8~5 EXAMPLE 5 - (Series E) Runs 40 to 58 inclusive were prepared as in the aforementioned general procedure. The furnish preparation, retention aids used, and order of material addition were as those described in Example 2 excepting that the filler used was pigmented (rutile titanium dioxide) vesiculated polymeric granules. The granules used were in the emulsion form as prepared and described in the foregoing text. The filler levels were 5 and 10 weight percent on pulp weight.
The results are shown in Table 5, also included are runs 9, 11 and 22 from Table 2 for ease of comparison of -33- :~LZ80544 C-I-L 711 ~ u~ r o er o~ ~ ~o ~
H Ul ~ ~ ~~ D ~ ~ O O ~9 ~r ~D 11~ ~ IJ~ O el~
~ ............ ~
O r 1` ~ r` 1` t~ 1` 1~ 1` r- r` o~ 1` 1` 1` GO 0~ 0~ OD r`
d~ _ .
~ ~ I I I I I I I I I I I I I I I I I
O ~ I I I I I I I I I I I I I I ~ I I I I
O H
O
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~;
~ IIOIOOOO~rOOIIOIIOIII
U~
~ 0~ I dP t 1 ,, 1 1 1 1 1 1, O O O O O, O u~
E~
-~.q ~ g~ IIIOIIIIIIIIIIIIIIII
O ~ d~ dP dP
n _~ ~ d~ 1 dP
~ U~=: _1:::: ~:::::: _1:::
~ ¦ ~ N ¦
. ~
~ ~ ~ ~ ~ ~i In ~ I` 0~ a~ o ~
, ~L2a~5~
EXAMPLE 6 - tSeries F) Runs 59 to 65 inclusive were prepared as in the foregoing general procedure. The furnish preparation, retention aids used, and order of material addition were as those described in Example 2 excepting that the filler used was a 1:1 weight ratio blend of pigmented (rutile titanium dioxide) vesiculated polymeric granules and anatase titanium dioxide. The granules used were in the emulsion form as described in the foregoing text. The anatase titanium dioxide was used as a mill base disperson as described in Example 2. The filler levels were 5 and 10 weight percent on pulp weight.
The results are shown in Table 6, also included are runs 9 and 11 from Table 2 and runs 42 and 44 from Table 5 for ease of comparison of results.
1 280~;4f~ C-I--L 71. ~
u~ D O In D
n o ~
~r ~ ~r~ c~ ~ ~ ~ r-& I`
, ~ U~
d' Q) ~ l l l l l l l l l l u) ~ II I I I I I I N
O H
a .~ ~ t ~I t I I I t o . _ ~ ~
a) ~ l ll l l l l l l l ~ ~ I II I II I ~r I I I
~; _.~
~q ~ l l l l l l l l l l rLl ~ I I I I I I ~ I I I I
H _ dP
~; ~ oP I ~ O I d~ ~
~ .~ u~
U~
:~ ~1 I I I I I I I I t I t .
o ~
10 dP ~ -I ~ dP dP
_l ~ :~ I u~
~ ~ ,.
o'P O O d~
u~ , E~
~ '~a ~ Eo~ V,~ E EE,::::
u~ ~a~ a~ ~+
I .,, + O + + + ~ + . ~ .
. ~ ~ ~ U~
~ . ~ O
~8~5~4 EXAMPLE 7 - (Series G) Runs 66 to 75 inclusive evaluated a hardwood furnish with a filler comprising a blend of pigmented (rutile titanium dioxide) vesiculated polymeric granules and non-pigmented vesiculated polymeric granules with and without retention aids. These eleven runs were prepared as in the foregoing general procedure. The furnish preparation, retention aid use, and order of material addition were as those described in Example 2 except that the filler used was a 1:1 weight ratio of pigmented vesiculated polymeric granules and non-pigmented vesiculated polymeric granules.
The results are shown in Table 7, also included are runs 27, 29, 32, and 38 from Table 3 and runs 42, 44, 50 and 15 55 for ease of comparison of results. ~
-~7- ~Z8~)5~ C-I-L 711 ~ ~ ~ ~ I~ ~ o ~ o U~ o . . . ~
_ ~ ~ l l l l l l l l l l l I
O ~
.~ ~ I l I I I I I I I~
o ~ _ .
~ ~ b l l l 1 1 ~ ~; ... . . .
H ~1 1/1 --~
u~ I ~ _~ I In ~: : : In I
. ... _ /Y .~ ~ ~ I
~ . _ ~ : : : _ U~:::::
~ g)~ 'g .__ ~' I` ~ 0 ~ o ~ i o ~r ~D ~ ~r ~D ~D ~D 1` 1` ~ .n . _ __ . _. .
3~ 1 ~8~)S4~ C-I-L 711 . _ ~ o ~
5~ o~
~ oo o ~
.~. , n o~
_ I ~ I I
o _ ~:
:~ ~ ~
H ~
E~ ~
U~ ~ l l l l l I
E'~
* dP ~
1~ 1~ I
O ~
~ ~ ~ ~* ~
C ~ ~ I : : _ :
~ i!~
,~'+
_ :~ ~ r ~
. . .
~280S4at EXAMPLE 8 -- (Series H) Runs 76 to 86 inclusive evaluated a hardwood furnish with a filler comprising a pigmented (rutile titanium dioxide) vesiculated polymeric granule with a median diameter of 12 microns, with and without retention aids.
These eleven runs were made as in the foregoing general procedure. The furnish preparation, retention aids used and the order of material addition were as those described in Example 2 except that the filler was an emulsion form of the pigmented vesiculated polymeric granules.
The results are shown in Table 8. -- - 4 - 1280544 c- -I. 7 1 1 H ~ I` ~ ~ ~10 C1~ 00 0 ~ l & ~ x ~r x er _ ~
o ~ I I 1 1,1 1 1 1~1 1 a .~ ~ ~ r :C o ~
~ ~ I I I 1 1~1 1 1 1 1 o~
~ ~ I I I lerl I I I I I
.~ ~ I I I I I I I I I I I
_ t ~ ~ I I I I I I I I I I I
CO ~
~ o 3~ dP
m ~
~ ~ ~ , i ~:: ::
+ ~.
g~ : : : : : : : : : :
~D oo a` X -i CC~ cO OD C~ 0 ~Z80S4~
EXPERIMENT 9 -- (series I) Runs 87 to 94 inclusive were performed with a hardwood pulp, filler comprising pigmented (rutile titanium dioxide~
vesiculated polymeric granules of median particle size 12 microns and non-pigmented vesiculated polymeric granules of median particle size of 5 microns, and retention aids.
These eight runs were made as in the foregoing general procedure. The furnish preparation, retention aids used, and the order of material addition were as the method described in Example 2 except for the filler composition which was an emulsion form of the pigmented and non-pigmented vesiculated granules.
The results are shown in Table 9 including runs 76 and 78 from Table 8 and runs 9 and 11 from Table 2 for ease of comparison.
-42- 1 ~8054~1 C-I-I. 7~ I
~; 1~ N ~ r ~ o q ~) o tY~ ~I N N U~ _I ~) d ' ~: ~ ~ ~ u~ In ~ ~ O~ 0~ 0 r o dO I . _ _ . o ~ l I I I I I I 1_1 1 ~ ~ I I I I I I I I I ~
c H~) ~ 1 7 1 I I I I I ~
~ _ u7 ~ I I I I I I I ~ I I I I _ E l N ¦ ~ : : N IJ I
U~ ~ ~
~ ~ l l l l l l l l l l l I
,1 C ~
O ~'-~_I ~ ~ ~d N It~ I Ltl: N 11~
~ l i m ~ dP ~ N _1 111 I
~t I ~ I
I -~ I` ~ a~ co oo o' _~ ~
- . . .
~ 280544 EXPERIMENT 10 - (Series J) Runs 95 to 102 inclusive were performed with a hardwood pulp, filler comprising a blend of pigmented (rutile titanium dioxide) vesiculated polymeric granules of median 5 particle size diameter of 12 microns and non-pigmented vesiculated polymeric granules of median particle size of 5 microns, with and without the use of retention aids. These eight runs were prepared as in the foregoing general procedure. The furnish preparation, retention aid used, and 10 order of material addition were as those described in Example 2 except that the filler used was a 1:1 weight ratio blend of the pigmented and non-pigmented vesiculated polymeric granule emulsions.
The results are shown in Table 10 including runs 76 and 15 78 from Table 8, runs 27 and 29 from Table 3 for ease of comparison of results.
44- ~280~;44 C-I-L 711 cn Ln o~ r~ ~ o ~ ~D Ln o o~ n Ln ~ u~
~r Ll~ ~ n .n ~r ~D Ln ~ Ln o & ~ ~
_ ~
~ Ln 2 = ~ 2 ~ 2 ~ F~ I I I I I ~ I I I 1~1 ~ ~ I I I I I I I I I~
v r~ ~
~; ~ I I I I I I I I er I I I
H _ ~ I I t l I I I ~
t~n ~ ~1 11 111 11111 ~ ~ 1~ H ~`~ I Ln I I ~ : : Ln o ~
, l~g 1~ , ~ LdnP I n ,~ I ~: : : LdnP
~ ~ i ._ _ i e ~ dP dnP :: ,~:: n::: _l . ~ ~ l j w ~D g ~ ~ g ~ ~
g , ~
I . . .
Ln LD ~ 0 ~n o o o , ~Z80~;44 Discussion of Tabulated Results It can be seen from Table 1 - (Series A) that the use of retention aids in combination with the fully bleached S chemical hardwood kraft pulp, does not contribute to any significant change in percent opacity. Thus, any gains in opacity reported in the following series can be directly attributed to interactions between the fillers, retention aids and pulp. The decrease in opacity observed in furnishes adjusted to neutral or alkaline conditions may be attributed to small repulsive forces increasing as the level of free negatively charged hydroxide ions was increased. In the furnish, which is already anionic in nature, these forces may decrease retention of the pulp flocs.
It can be seen from Table 2 (Series B) that at the 5%
filler level the maximum percent opacity obtained was with the use of Alum as a retention aid (79.47%). It can also be seen that pulp with anatase titanium dioxide, in the absence of a retention aid, shows no significant change in % opacity as the pH changes from acid to alkaline. The presence of retention aids renders the pulp plus anatase titanium dioxide furnish slightly more sensitive to changes in pH
when observing % opacity. The degree of difference is still quit,e small.
It can be seen from Table 3 (Series C) that at the 5%
filler level the maximum percent opacity obtained was with the use of the retention aid dimethylamine epichlorohydrin (76.87). A further gain of 0.8% opacity was obtained when the pH was increased from 4.5 to 8.5. At the 10% filler level the maximum percent opacity was also obtained with the use of the retention aid dimethylamine epichlorohydrin (79.27).
It can also be seen from Table 3 that when the pH of pulp with vesiculated granules was raised from 4.5 to 8.5 a small decrease in % opacity was observed when the pH was ~Z80S44 raised in the furnish which contains the dimethylamine epichlorohydrin, pulp, and vesiculated granules (runs 32 and 33) an increase % opacity was observed. Run number 35 which demonstrated the effect of alkaline pH on a furnish containing Alum was included as a known control. It is known in the papermaking field that Alum is useful only in acidic papermaking due to its chemical structure and ionic nature. Run 35 demonstrated the expected drop in opacity of Alum used in an alkaline furnish.
It can be seen from Table 4 - (Series D) that when vesiculated polymeric granules and anatase titanium dïoxide were combined to form a filler at acidic pH, an enhancement of % opacity could be gained over the use of anatase titanium dioxide alone as a filler. This feature was observed for both 5 and 10 percent filler level on pulp.
It can be seen from Table 5 - (Series E) that % opacity gains of a significant amount were obtained with the use of pigmented vesiculated polymeric granules over anatase titanium dioxide. Comparing the two fillers without the use of retention aids at the 5% filler level on pulp (runs 42 and 9) a gain of 0.7 percent opacity was achieved. At the 10 percent filler level on pulp (runs 44 and 11) a gain of 0.4 percent opacity was achieved. With the use of retention aids comparing 5 percent filler level on pulp, the anatase titanium dioxide sample using Alum achieved 79.5 percent opacity. This was compared to pigmented vesiculated polymeric granules with dimethylamine epichlorohydrin as the retention aid which achieved an opacity of 79.0 percent at pH 4.5 or 81.04 percent at pH 6.5.
When the level of pigmented vesiculated polymeric granules was increased to 10 percent on pulp weight and incorporated the use of dimethylamine epichlorohydrin as the retention aid an excellent opacity of 82.6 percent at pH 4.5 and 84.5 percent at pH 7.5 was achieved. This reflects a gain of 10 percent opacity units over the use of pigmented ~.280544 vesiculated polymeric granules without the use of a retention aid. This example illustrates the claims of this invention.
It can be seen from Table 6 (Series F) that the maximum percent opacity obtained in this Series (which is examining the effect of combining titanium dioxide and pigmented vesiculated granules together as a filler) was obtained when the blend was used at a level of 10 percent on pulp weight and incorporated the retention aid dimethylamine epichlorohydrin (81.20~ opacity). Runs 9, 42 and 59 show that at a 5% combined filler level the use of the pigmented granules was better for percent opacity than titanium dioxide alone. The blend of the two fillers gave a percent opacity value that was between that for the fillers separately. This effect was noticed at 5 and 10 percent filler levels.
The excellent response of the filler blend to all four retention aids demonstrated that where a particular retention aid would enhance opacity for one of the fillers, this enhancement was also observed in the blend of fillers.
It can be seen from Table 7 (Series G) that if the filler comprises a blend of both pigmented and non-pigmented vesiculated granules the percent opacity achieved was generally higher than for non-pigmented vesiculated polymeric granules as a single filler and slightly lower than pigmented vesiculated polymeric granules as a single filler. With the use of retention aids the blend of non-pigmented and pigmented vesiculated polymeric granules achieved percent opacities almost equal to the pigmented granules. This could mean that a paper sheet prepared with a properly tailored blend of pigmented and non-pigmented vesiculated granules could achieve a target percent opacity and have a corresponding reduction in weight and cost of the paper sheet.
.
~Z80544 It can be seen from Table 8 (Series H) that the larger median diameter (12 microns) pigmented vesiculated granules have an improved ~ opacity gain over anatase titanium dioxide and 5 micron diameter (median) pigmented vesiculated granules when used as a filler. The retention aid dimethylamine epichlorohydrin assisted in increasing the percent opacity gain.
It can be seen from Table 9 (Series I) that the blending of pigmented vesiculated polymeric granules (median diameter 12 microns) and anatase titanium dioxide to form a filler, did not give a significant increase in percent opacity over the use of the granules alone. The best retention aids for increased percent opacity were again noted to be dimethylamine epichlorohydrin and alum. Each retention aid contributing to the filler portion best suited to its structure, the DMA-EPI was definitely aiding the granules, and alum aiding the Tio2.
It can be seen from Table 10 (Series J) that the blend of larger median diameter (25 microns) pigmented vesiculated granules with non-pigmented vesiculated granules as a filler for a paper sheet achieved better percent opacity than by using non-pigmented granules only. The excellent increase in percent opacity obtained with the use of the retention aid dimethylamine epichlorohydrin could suggest that a paper sheet prepared with a properly tailored blend of pigmented and non-pigmented vesiculated polymeric granules could achieve a targeted percent opacity and have a corresponding reduction in weight and cost of the paper sheet.
-
Claims (16)
1. An aqueous composition comprising vesiculated polymeric granules and a retention aid; said granules having a mean diameter of 1 to 500 microns, the ratio of the granule diameter to the mean vesicle diameter being at least 5:1, the maximum diameter of the vesicles being 20 microns and the volume of the vesicles being from 5-95% of the volume of the granules.
2. A composition as claimed in Claim 1 in which the vesicles contain up to 100% by volume of a solid or liquid material.
3. A composition as claimed in Claim 2 in which the vesicles contain up to 45% by volume of said solid or said liquid material.
4. A composition as claimed in Claim 2 or 3 wherein said solid is an optical brightener.
5. A composition as claimed in Claim 2 in which the solid material is a pigment.
6. A composition as claimed in Claim 5 in which the pigment is titanium dioxide.
7. A composition as claimed in any one of Claims 1, 2 or 5 in which the volume of the vesicles is at least 20% of the volume of the granules.
8. A composition as claimed in any one of Claims 1, 2 or 5 in which the diameter of the vesicles is less than 5 microns.
9. A composition as claimed in any one of Claims 1, 2 or 5 in which the granules have a diameter of 1-50 microns.
10. A composition as claimed in any one of Claims 1, 2 or 5 in which the volume average diameter is from 5 to 35 microns.
11. A composition as claimed in any one of Claims 1, 2 or 5 and further comprising paper additives selected from the group consisting of sizing material, wet and dry strength additives, defoamers, biocides, dyes, fillers, starches and optical brighteners.
12. A composition as claimed in any one of Claims 1, 2 or 5 and further comprising a pigment or non-pigment filler.
13. A composition as claimed in any one of Claims 1, 2 or 5 and further comprising titanium dioxide.
14. A composition as claimed in any one of Claims 1, 2 or 5 and further comprising a fibrous cellulosic or non-cellulosic material.
15. A composition as claimed in any one of Claims 1, 2 or 5 and further comprising a fibrous cellulosic material.
16. Paper containing dispersed therein vesiculated polymeric granules as defined in Claim 1 and a retention aid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000515822A CA1280544C (en) | 1986-08-12 | 1986-08-12 | Vesiculated polymer granular compositions and paper made therefrom |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000515822A CA1280544C (en) | 1986-08-12 | 1986-08-12 | Vesiculated polymer granular compositions and paper made therefrom |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1280544C true CA1280544C (en) | 1991-02-19 |
Family
ID=4133719
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000515822A Expired - Lifetime CA1280544C (en) | 1986-08-12 | 1986-08-12 | Vesiculated polymer granular compositions and paper made therefrom |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1280544C (en) |
-
1986
- 1986-08-12 CA CA000515822A patent/CA1280544C/en not_active Expired - Lifetime
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