FI61509C - BELAEGGNINGSVAETSKA ANVAENDBAR FOER FRAMSTAELLNING AV LYOFOBA ELEKTRISKT LEDANDE SKIKT - Google Patents

Description

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Patent · och ragitterstyralsan Aniskin uttajd och uti.ikrifter pubikend 30.00.82 (32) (33) (31) «products * —B * ftrd priori * * (71) Calgon Corporation, Route 60-Campbell's Run Road, Robinson Township, Pennsylvania , USA (US) (72) Robert Henry Windhager, Pittsburgh, Pennsylvania, USA (US) (7 * 0 Oy Kolster Ab (5I +) Coating liquid for the production of lyophobic electrically conductive layers - Beläggningsvätska användbar för framställning av lyofoba, elektriskt ledande skikt

The invention relates to a coating liquid for the production of lyophobic electrically conductive layers, which contains 15 to 50% by weight of an electrically conductive, water-soluble polymer, 30 to 70% by weight of an insulating, water-soluble, polymeric binder and 10 to 60% by weight of a pigment. The coating liquid according to the invention is characterized in that it additionally contains 0.5-10% by weight of mono- and / or bisOH, 1H, 2H-2H-perfluoroalkyl) phosphate of the formula

(CmF2m »1cnH2n0'yPO'OM) 3-y I

wherein m is an integer from 4 to 10, n is an integer from 1 to 11, y is 1 or 2 and M is an alkali metal ammonium or substituted ammonium cation.

Generally, electrically conductive substrates used to make electrophotographic papers are made by applying a resinous layer, 2 * 1509, to one or both surfaces of a suitable paper substrate (printing paper, basis weight 49-73 g / m 2) which makes the paper electrically conductive. Usually the electrically conductive layer is formed by the electrically conductive polymer either alone or more usually together with a binder (usually a water-soluble, non-conductive, film-forming polymer such as protein, starch, styrene-butadiene latexes, modified or modified starch, casein, polyvinyl acetate, polyvinyl acetate, with a pigment (such as calcium carbonate, kaolin clay, titanium dioxide, alumina or a combination of these substances). Electrophotography remained in the printing paper industry such compositions containing a conductive substance, a binder and a pigment are commonly referred to as coating dye compositions or coating liquids.

In conventional conductive coating ink compositions, the purpose of the binders is to make the paper less porous, more uniform in quality, to improve the adhesion of the electrically conductive layer to the substrate, and most importantly to provide conductive barrier properties to prevent solvents used in photosensitive layers. The separate non-conductive and solvent-retaining layer comprises one conventional binder or a mixture of such binders applied to the paper prior to applying the conductive layer to provide a solvent barrier effect. The solvent-retaining effect on both toluene and paraffinic solvents is essential because the top side of the conductive substrate paper comes into contact with toluene upon subsequent application of a photosensitive coating of color-sensitized zinc oxide dispersed in a solution of toluene and binder. The underside of the zinc oxide coated backing paper (called finished "Electrofax" paper) comes into contact with the kerosene during the deinking process in "Electrox" copiers using "wet" tinters formed by carbon particles suspended in a solution of kerosene and binders. The usual type of electrically conductive polymer in combination with conventional types of coating additives such as the above-mentioned binders and pigments does not result in acceptable solvent inhibition when applying commercially acceptable coating weights of 1.6-6.5 g of coating per square meter of paper surface. with a separate solvent barrier.

3 61 509

The present invention is based on the finding that the solvent barrier properties of conventional coating fluids formed by electrically conductive polymers, binders and pigments commonly used in such compositions can be greatly improved by adding to such compositions an effective amount of fluorocarbon of formula I. It has been found that the improved coating fluids of the present invention provide an electrically conductive substrate with surface resistivity, zinc oxide coating, waste paper reuse, and improved solvent barrier properties that are commercially acceptable in accordance with non-standard for the raw material (raw material whose surface has not been treated with starch, alginate or other surface adhesives). Thus, the coating liquids according to the invention not only provide improved solvent barrier properties, but also make it possible to apply an electrically conductive layer to the substrate by a single-step treatment, in which case it is not necessary to apply a separate solvent barrier layer. The specific surface resistance, zinc oxide coatability, waste paper reuse, and solvent barrier properties achieved using the improved coating fluids of the invention have been determined using standard laboratory techniques. Thus, suitable coating weights for the improved coating liquids of the invention can be used in the manufacture of electrically conductive substrates suitable for the production of electrophotographic and electrographic resin papers.

The type of electrically conductive polymer component of the coating fluids of the invention is not critical. Any electrically conductive polymer, both cationic and anionic, can be used provided that the selected conductive polymer can provide adequate surface resistance to the substrate (industry requirements for conductivity in substrate plates are 10 μm per square_7 at 15% relative humidity). As the cationic electrically conductive polymers, any water-soluble cationic polymer containing quaternary ammonium groups can be used. Such cationic polymers include those in which the quaternary ammonium group is a polymer backbone-dependent group, such as, for example, polyvinylbenzyltrimethylammonium chloride, poly (alpha (methylene trimethylammonium chloride) ethylene oxide) and polymethacryloxyethyltrimethylethylethyl; those in which the quaternary ammonium group is contained in a 61509 cyclic structure comprising a portion of a polymer backbone, such as, e.g., poly- (dimethyldiallylammonium chloride); and those in which the quaternary ammonium group forms part of a polymer chain, such as cationic polymers, commonly referred to as "ions".

This group includes, for example, ionic polymers prepared from haloalkyl dialkylamine monomer units, such as 3-ionicene (poly (dimethylpropyl) ammonium chloride) prepared by polymerizing 3-chloropropyldimethylamine, and ionic polymers, prepared from di-tert-aramines and dihalides such as 3,4-ioninene prepared from 1,3-bis-dimethylaminopropane and 1,4-dichlorobutene. Other ion-ene polymers prepared in a similar manner can, of course, be used in the coating fluids of the invention as an electrically conductive component.

In addition to the above-mentioned cationic electrically conductive polymers, water-soluble cationic phosphonium and sulfonium polyraers can also be used as the electrically conductive component in the coating liquids according to the invention. These include, for example, polymers such as poly (2-acryloxyethyldimethylsulfonium chloride) and poly- (glycidyltributylphosphonium chloride) and the like.

The water-soluble anionic polymers used in the preparation of the coating liquids of the invention are typically polymeric acids and alkali metal and alkaline earth metal salts. Such anionic polymers include, for example, poly (sulfostyrene) poly (allylsulfonic acid), sulfonated urea-formaldehyde resin, sulfonated polymethylolacrylamide, and the like.

It should be noted that the typical cationic and anionic polymers mentioned above may contain one or more other meric units. For example, copolymers such as a copolymer of dimethyldiallylammonium chloride and diacetone-acrylamide or a copolymer of styrene and maleic acid can also be used as the electrically conductive component of the coating liquids according to the invention. The ratio of mere units in such copolymers is determined by the number of cationic or anionic units required to obtain the desired specific surface resistance in the support.

Although any of the above conductive polymers or other conductive polymers that can provide the specific surface resistance required for the 61509 substrate can be used as the conductive component in the coating fluids of the invention, preferred conductive polymers include cationic polymers and copolymers and especially cationic quaternary quaternary copolymers. Of these, the most preferred polymers are copolymers of poly (dimethyldiallylammonium chloride), dimethyldiallylammonium chloride and diacetone-acrylamide copolymers, containing 70-98% diallyl monomerylmethylimethyltrimethoxymethyltrimethylenexyl monoxylmethylimethylmethylimethylamethrylamide, hydrin quaternized 80-100% with trimethylamine, copolymers of acrylamide and methacryloxyethyltrimethylammonium chloride containing 90-99.5% methacryloxyethyl monomer, and poly- (methacryloxyoxyethylmorium) dimethylhydroxyethyl

As stated above, the binders used in the coating fluids of the invention can vary widely and do not form a critical part of the invention. Any water-soluble, non-conductive, film-forming polymer conventionally used for this purpose can be used. Suitable binders include, for example, polyvinyl alcohols, polyvinyl acetates, styrene-butadiene latexes, polyethylene-polyvinyl acetate copolymers, unmodified starches, acetylated starches, acid starches and starches thereof, hydroxyethyl starches, other starches, enzymes Likewise, any pigment conventionally used in coating color compositions can be used in the improved coating color compositions of the invention, such as commercially available calcium carbonates, kaolin clays, titanium dioxide, alumina, or combinations of these agents.

The fluorocarbon component of the improved electrically conductive coating fluids of the invention is essential for obtaining improved solvent barrier properties in improved coating paint compositions. It has been found that certain mono- and bis- (1H, 1H, 2H, 2H-perfluoroalkyl) phosphate esters, when added to electrically conductive coating fluids, effectively improve solvent retention properties. Useful perfluoroalkyl phosphate esters have the formula (cmF2m + 1CnH2nO2 yPO3-y where m is an integer from 4 to 10, n is an integer from 1 to 11, y is 1 or 2 and 61509 M is a water-soluble alkali metal (Li, K, Na and the like), ammonium or substituted ammonium cation including methylamine, dimethylamine, diethylamine, monoethanolamine, diethanolamine, triethanolamine or morpholine, etc. Preferred salts are generally diethanolamine salts, If desired, C and C together form a straight chain of at least 8 carbons. Perfluoroalkyl phosphate esters are well known substances and are commercially available or can be readily prepared by known methods, with Perfluoroalkyl Phosphate Ester being manufactured by EI du Pont de Nemours Company, Inc. under the trademark "ZONYL RP" in Wilmington, Delaware, containing diethanolamine salts of mono- and bis- (1H, 1H, 2H, 2H-perfluoroalkyl) phosphates with the alkyl group is numbered evenly in the range C8-C18 and the fluorine content of the salts is 52.4-54.4% as determined from the solids.

Although any of the binders or mixtures of binders described above can be used in the coating fluids of the invention, mixtures of polyvinyl acetate and polyvinyl alcohol are preferred. Polyvinyl acetate may be present in an amount of 20 to 50% by weight of the composition and polyvinyl alcohol may be present in an amount of 10 to 40% by weight of the composition. When polyvinyl alcohol is used in the binder, it is preferable to add 1-15% by weight of melamine to the composition as a polyvinyl alcohol crosslinker. Thus, preferred coating liquids according to the invention include:

Component Weight% of component in dry coating Electrically conductive polymer 15-50

Polyvinyl acetate 20-50

Polyvinyl alcohol 10-40

Fluorocarbons 0.5-10

Melamine 1-15

Pigment 10-60

To illustrate the benefits of the coating fluids of the invention, experiments were performed in which the fluorocarbon-containing coating fluids of the invention and corresponding fluorocarbon-free fluids were used as aqueous emulsions to coat both surfaces of a non-surface bonded base paper (50.5 g / m 2 basis weight). The base papers were coated by pulling along the surface with a rod twisted with a wadding according to standard practice. The plates were dried in a 7 61509 photographic weight dryer 15 seconds after coating.

After aeration at 50% relative humidity for at least 4 hours, a portion of the plates were tested for solvent resistance by contacting the plate with a dye solution (Solution A: 100 g toluene, 35.8 g polyvinyl acetate, 0.65 g 4 - / '(4-methylphenyl) amino). 11-hydroxy-9,10-anthracenedione, and solution B: petroleum + 2% flame red) for 10 seconds; the dye solvent was immediately wiped off the plate; visually examined the other side of the plate and determined penetration. The block order was based on the comparison table used in TAPPI (Technical Association of the Pulp and Paper Industry) New Provisional Method T-528. After being aerated at a relative humidity of 15% for at least overnight, the specific surface resistance of the second part of the plate was examined using an 8.57 cm diameter disc made of the plate and an electrometer. The following are typical results of the experiments.

Example 1

Component% by weight of component in dry coating poly- (dimethyldiallylammonium chloride 20 polyvinyl acetate 35 polyvinyl alcohol 26 calcium carbonate 15 melamine 4 100% 2 The coating (6.5 g / m 2) was applied to both sides of the base paper. The penetration rate of Solution A was 60% and the penetration rate of Solution B was 90%.

61 509 8

Example 2

Component% by weight of component in dry coating polyvinylbenzyltrimethylammonium chloride 20 styrene-butadiene latex 31 polyvinyl alcohol 30 kaolin clay 15 melamine 4 100% 2 The coating (6.5 g / m 2) was applied to both sides of the base paper. The coated plate had unacceptable solvent inhibitory properties. Solution A had a penetration rate of 40% and solution B had a penetration rate of 80%.

Example 3

Component% by weight of component in dry coating polyvinylbenzyltrimethylammonium chloride 22 polyvinyl acetate 31 polyvinyl alcohol 10 calcium carbonate 35 melamine 2 100% 2 The coating (6.5 g / m 2) was applied to both sides of the base paper. The coated plate had unacceptable solvent inhibitory properties. Solution A had a penetration rate of 60 and solution B had a penetration rate of 90%.

Example 4

Component Weight% of component in dry coating poly- (dimethyldiallylammonium chloride) 22 polyvinyl acetate 32 polyvinyl alcohol 12 calcium carbonate 30 perfluoroalkyl phosphate 2 melamine 2 100% 9 61509 The coating (4 g / m) was applied to each side of the base paper. The coated sheet had acceptable solvent barrier properties. The penetration rate of solution A was less than 4% and the penetration rate of solution B was 15%.

The specific surface resistance at 15% relative humidity was 7.4x10 ^ ohms per square on one side and 3.8x10 ^ ohms per square on the other side. The standard industry requirements for resistivity in base papers are 15% or less at 10% relative humidity.

With a zinc oxide composition ^ 200 g of zinc oxide, 60.5 g of polyvinyl acetate, 205.5 g of toluene, 0.25 ml of bromophenol blue (2.5% by weight in methanol), 0.75 ml of spiro / isobenzofuran-1 (3H), 9 The disodium salt of (9H) -xanthene-7-one (2.5% by weight in methanol), 0.40 ml of acid green 16 (2.5% by weight in methanol), was coated on the wool side of the plate and the resulting dry coating was smooth and free of cracks ( i.e., "outages").

Several electrically conductive coated substrate plates (without zinc oxide coating) were treated in a cholester and then made into plates by hand. The handmade sheets obtained were of good quality and no clumping of fibers could be detected.

Example 5

Component% by weight of component in dry coating polyvinylbenzyltrimethylammonium chloride 22 polyvinyl acetate 28 polyvinyl alcohol 10 calcium carbonate 35 perfluoroalkyl phosphate 3 melamine 2 100% 2 A coating (4.4 g / m) was applied to each side of the base paper. The coated plate had acceptable solvent barrier properties. The penetration rate of solution A was less than 2% and the penetration rate of solution B was 10%. The specific surface resistances were 8.5x1010 ohms per square on one side and 8.4x10 ^ ohms per square on the other side at a relative humidity of 15%. The zinc oxide coating applied to the batt side was free of streaks and cracks and the conductive coated substrate (non-zinc oxide coating) was of good quality.

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Example 6

Component Weight% of component in dry coating polyepichlorohydrin quaternized triple ethylamine 22 polyvinyl acetate 28 polyvinyl alcohol 10 calcium carbonate 35 perfluoroalkyl phosphate 3 melamine 2 100% 2 A coating (4.7 g / m) was applied to the base paper. The coated plate had acceptable solvent resistance and specific surface resistance properties. The penetration percentage of solution A was less than 2%. The specific surface resistances were 5.6x10 ohms per square on one side and 3.3x1010 ohms per square on the other side at a relative humidity of 15%. The electrically conductive coated plates (without zinc oxide coating) had good processability and the zinc oxide coating was easy to apply to the substrate.

Claims (5)

61. O 9 11 Coating liquid for the production of lyophobic electrically conductive layers, containing 15-50% by weight of an electrically conductive, water-soluble polymer, 30-70% by weight of an insulating, water-soluble, polymeric binder and 10-60% by weight of a pigment, characterized in that the coating liquid further contains 0.5-10% by weight of mono- and / or bis- (1H, 1H, 2H, 2H-perfluoroalkyl) phosphate of the formula (cmF2m * 1CnH2n0lyp0 (0M) 3-y 1 where m is an integer 4-10, n is an integer from 1 to 11, y is 1 or 2 and M is an alkali metal, ammonium or substituted ammonium cation. Coating liquid according to Claim 1, characterized in that it contains a straight-chain perfluoroalkyl phosphate of the formula I in which M is diethanolamine and m + n is 8 to 18. Coating liquid according to Claim 1, characterized in that it contains a quaternary cationic ammonium polymer as electrically conductive polymer. Coating liquid according to Claim 3, characterized in that it contains, as ammonium polymer, poly- (dimethyldiallylammonium chloride), dimethyldiallylammonium chloride-diacetoneacrylic acid amide copolymer containing 70-98% of dimethyldiallylammonium units, polymethylbenzyltrimethylamethylamethylamphenyltrimethylamine -methacryloxyethyltrimethylammonium methosulfate, 80-100% quaternary polyepichlorohydrin trimethylamine, acrylic acid amide-methacryloxyethyl-ammonium / methyryl-acrylide; Coating liquid according to Claim 1, characterized in that it contains, as binder, a mixture of 20 to 50% by weight of polyvinyl acetate, 10 to 40% by weight of polyvinyl alcohol and 1 to 15% by weight of melamine.