CN1018029B - Zinc oxide xeroprinting boards - Google Patents

Abstract

The present invention relates to a zinc oxide xeroprinting board which belongs to a photoconductive functional material used for printing. A coupling agent and a metallic salt are used in the conducting layer of the zinc oxide xeroprinting board, an ionic surfactant is used in a protective layer on the back side, a metallic salt and inorganic powdery material are used in a blocking and bonding layer, and organosilicon and a silane coupling agent are used in a sensitive layer. In the manufacturing process of the present invention, a conducting layer with toxic raw materials is not used; simultaneously, the present invention has the characteristics of low price, good photoelectric properties, easy board manufacture, high printing resistance, capability of printing more than 3000 split pages, etc.; as a novel board material for printing, the zinc oxide xeroprinting board is used for the photocopy of books, a typesetting board-making system by electrophotography and a board-making system by using computer composition.

Description

Zinc oxide xeroprinting boards

The invention belongs to a kind of photoconductive function material that is used to print.

In prior art, zinc oxide electrostatic offset plate normally is coated with conductive layer identical or inequality respectively on the paper substrate two sides, and coating stops tack coat on the conductive layer in front, again photosensitive coated layer in the above.Most cation type polymer-polychlorostyreneization vinyl benzyl the trimethylammoniums (following employing is called for short ECR) one to one that adopt of state outer conducting layer, as document: the holt tree, the filial piety of first paddy light, middle village justice man " special paper medicine " 1984, a day disclosure is speciallyyed permit clear 60-107041; Day disclosure is speciallyyed permit among the clear 57-176062 and is reported.Use Chlorodimethyl ether in making the ECR process, it is a kind of strong carcinogen, thereby to using ECR to be subjected to certain restriction.State's inner conducting layer generally is molten aqueous solution (as polyvinyl alcohol water solution) or the middle coating of aqueous emulsion (as polyvinyl acetate emulsion) that mixes macromolecule resin of inorganic salts (as sodium sulphate, sodium chloride etc.).Also have and adopt containing water soluble salt (as sodium sulphate, sodium chloride etc.) water-insoluble salt (as barium sulphate) dissolves and is dispersed in coating in the natural polymer aqueous solution (as gelatin gels solution), and makes bonding crosslinked after coating with macromolecule with crosslinking chemical (as formaldehyde).The electric conductivity of the conductive layer that makes with these methods, water resisting property, cohesiveness, performances such as toughness and intensity are all not as good as ECR, and conductivity is subject to the influence of ambient humidity, thereby cause the residual electric potential height of electrostatic offset plate, the luminous sensitivity deficiency, bottom ash is big, and plate-making is difficulty relatively, the printing number is few, and the versatility under the different humidity weather conditions is poor.Photographic layer generally only uses the copolymer acrylate class binding resin of various models, and its surface potential V0 is the highest only about 450 volts, sometimes even be lower than 200 volts.And Zinc oxide powder self can aggegation be bigger particle in photographic layer, zinc paste disperses unstable in resin like this, resin-bonded ability is relatively poor, photo-generated charge carriers is higher through the barrier potential of zinc oxide surface transmission, and these defectives have all influenced the mechanical property and the photoconductive property of product significantly.

The objective of the invention is to use a kind of raw material to be easy to get, inexpensive, conductance is high and influenced by ambient humidity very little, does not particularly use the conductive layer of poisonous raw material in manufacture process, a kind of intensity height, and water resisting property is good, the back-protective layer of good conductivity; A kind ofly in water, do not dissolve, swelling deformation does not take place in printing process, have the tack coat that stops of excellent adhesion and toughness; A kind of surface potential can be controlled as required, can make zinc paste fine dispersion in binding resin, bonds well, and the barrier potential that makes charge carrier pass through zinc oxide surface reduces, the photographic layer that mechanical property and photoconductive property are good so just can make a kind of Zinc oxide xeroprinting boards of high comprehensive performance.The plate-making of this offset printing paper mold is easy, uses easy to operately, and the space of a whole page is superior in quality, splits the space of a whole page and can print more than 3000.

Principal feature of the present invention adopts titanate esters (as KR-138S TA-9, TCP-114 etc.) or silane coupling agent (as KH-550, A-150, A-171 etc.) or both to be used in combination in conductive layer.Group and alkaline metal salt (as sodium sulphate, sodium chloride, lithium chloride, aluminium sulphate etc.) generation chemical actions such as the hydroxyl in this coupling agent and the paper substrate cellulose, the product of generation has stable strong ionic conduction effect.The concentration of metallic salt aqueous solution is 0.1-10%, preferably 0.8-2%.The coupling agent consumption is the 0.01-0.5% of slaine, and preferably 0.1-0.5% is impregnated-paper-based with this solution or emulsion.Some coupling agent can also make cellulose produce certain cross-linked structure, improves paper substrate intensity.Therefore use coupling agent can improve the conductivity that contains cellulosic material, do not use poisonous raw material, conductivity height and the ambient humidity vary stable.It also can be used to make the fabric etc. of the fibre-bearing element of conductive paper and conduction.

Another characteristics of the present invention are in the polymer emulsion of protective seam coating, to add quaternary ammonium salt cation surfactant or alkyl sulfonate type anionic surfactant and increase electric conductivity overleaf.Polymer emulsion has polyvinyl acetate emulsion, vinyl chloride-vinyl acetate copolymer emulsion, acryl resin SB emulsion, acryl resin BN emulsion, the neutral emulsion of acryl resin, the soft emulsion of acryl resin, soft No. two emulsions of acryl resin etc.The solid content of used emulsion is in the 0.1-50% scope, and preferably (solid content is meant the number percent of solid matter content in emulsion or the solution to the 1-10% scope.）。Ionic surfactant has alkyl sulfonate type anionic surfactant: sodium dodecylsulphonate, neopelex, to ABPS etc., quaternary ammonium salt cation surfactant: octadecyl diformazan hydroxyethyl quaternary amine nitrate, the hexadecyldimethyl benzyl ammonium ammonium bromide, trihydroxyethyl methyl quaternary amine Methylsulfate etc.The base consumption is the 0.05-5% of resin, preferably 0.1-2%.Also can add the conductive carbon black of amount of resin 0-100%, preferably 10%-20%; Or the aquadag of amount of resin 0-300% (solid content is 20%-25%), preferably 15%-30%.

Another characteristics of the present invention are used the inorganic powder of metal halide salt and alkaline earth oxide in stopping tack coat.Be coated with by high polymer binder the restraining barrier that metallic salt and inorganic powder are formed, the neutral glue of high polymer binder such as polyvinyl formal in the paper substrate front, the Pioloform, polyvinyl acetal bonding agent, butyral varnish, polyvinyl butyral etc., concentration 1-20%, metallic salt such as sodium sulphate, sodium chloride, sodium sulphite, lithium chloride, bismuth iodide, cuprous iodide etc., its concentration is 0.005-1%, preferably 0.01-1%.Inorganic powder such as potter's clay, porcelain earth, lime carbonate, titanium dioxides etc., inorganic powder add the bottom ash in the time of can reducing static plate-making, and its consumption is the 10%-300% of resin, preferably 50-100%.

Another characteristics of the present invention are used organosilicon and silane coupling agent in photographic layer.Blend polysiloxane in the acryl resin that photographic layer uses, as fluorosioloxane rubber, room curing silicon rubber, dimethyl silicone polymer, polyphenyl methylsiloxane, transparent silicon resin, organosilicon epoxy resin etc.Organosilicon can improve the surface potential of electrostatic offset plate, can reach the 800-1200% volt, can regulate control as required, and the weight ratio of organosilicon and acryl resin is 5-300%.For increasing the dispersion stabilization of zinc paste in resin, further improve mechanical property and photoconductive property, add silane coupling agent, as γ-r-chloropropyl trimethoxyl silane, vinyl ('beta '-methoxy ethoxy) silane, γ-aminopropyl Ethoxysilane, consumption are the 0-5% of zinc paste amount, preferably 0.01-0.3%.Also available simultaneously hydroxyl polar material such as ethanol, water, ethylene glycol, glycerine etc. are regulated the rheologic behavio(u)r of photographic layer slurry, and consumption is the 0.5-10% of solvent total amount, and usual amounts is 2-6%.

Be embodiments of the invention and reference examples below:

Embodiment one:

30 parts of TCP-114 titanate esters, 20 parts of lithium chlorides, 60 parts in sodium sulphate, 70 parts in aluminium sulphate, 1000 parts in water, dip-coating asbestos base paper, be coated with by 100 parts in polyvinyl formal bonding agent (solid content 17%), 1 part of lithium chloride, 0.01 part of cuprous iodide in the front, the suspending liquid of 7 parts of compositions of porcelain earth, dry after super calendering is coated with photographic layer in the above, prescription is 100 parts on photosensitized oxidation zinc, 25 parts of 154 acryl resins, 5 parts of fluorosioloxane rubber, 0.1 part of rose bengal.5 parts of ethanol, 30 parts of toluene.Make electrostatic offset plate and on electrical machinery plant of Japanese Kawaguchi system SP428 static paper tester, test, charging voltage-6.8 kilovolt, white light exposure, illumination 30 luxs (following test condition is identical).Record surface potential V0=600 volt, dark decay speed (V0-V30)/V0=10%(V30 be stop to charge the back under dark condition the surface potential after 30 seconds), luminous sensitivity E1/2=20 lux second (time of 1/2 of the E1/2 initial potential that is the surface potential optical attenuation when exposing and the product of illumination), the residual electric potential Vr=40 volt after the exposure.Splitting space of a whole page printing number on the offset press more than 4000.

Embodiment two:

Conductive layer and restraining barrier be with embodiment one, at paper substrate back side stopping off: 3 parts of polyvinyl acetate emulsions (solid content 50%), 5 parts of polyacrylic acid SB emulsions (solid content 40%); 1 part of polyvinyl alcohol (PVA); 0.2 part of hexadecyldimethyl benzyl ammonium ammonium bromide, 20 parts of ethanol, the emulsion of 50 parts of compositions of water.The photographic layer prescription is 100 parts on a photosensitized oxidation zinc, 25 parts of 154 acryl resins, 12 parts of transparent silicon resins (solid content 50%), 0.1 part of rose bengal, 2 parts of ethanol, 10 parts of toluene, 20 parts of butyl acetates.Make electrostatic offset plate V0=800 volt, (V0-V30)/V0=10%, E1/2=18 lux second, the Vr=10 volt is split space of a whole page brush number more than 3000.

Embodiment three: conductive layer and restraining barrier are with embodiment one; the back-protective layer removes increases conductive carbon black 0.5 especially; all the other are with embodiment two; the photographic layer prescription is: 27 parts of 154 acryl resins; 3 parts of 665 organosilicon epoxy resins, 0.01 part in 593 hardening agent, 0.8 part in 107 silicon rubber; zinc paste, dyestuff and solvent are with embodiment two.Make electrostatic offset plate V0=500 volt, split space of a whole page printing number more than 5000, all the other performances are with embodiment two.

Embodiment four:

Conductive layer; restraining barrier and back-protective layer are with embodiment three; the photographic layer prescription is: 20 parts of 154 acryl resins, 6 parts of 665 organosilicon epoxy resins, 0.02 part in 594 hardening agent; 1 part of 664 vinylcarbinol ethylene oxidic ester; 0.07 part of gamma-aminopropyl-triethoxy-silane, 1.5 parts in 107 silicon rubber, 0.1 part in No. 2 hardening agent of silicon rubber; zinc paste, dyestuff and solvent are with embodiment three.Make electrostatic offset plate V0=650 volt, the Vr=20 volt is split space of a whole page printing number more than 6000, and all the other performances are with embodiment three.

Embodiment five:

Conductive layer, restraining barrier and back-protective layer are with embodiment three, and the photographic layer prescription is: 20 parts of 154 acryl resins, 10 parts of 665 organosilicon epoxy resins, 0.03 part in 594 hardening agent, 2 parts in 107 silicon rubber, zinc paste, dyestuff and solvent are with embodiment three.Make electrostatic offset plate V0=900 volt, the Vr=25 volt is split space of a whole page printing number more than 5000, and all the other performances are with embodiment three.

Reference examples one:

At the following solution of asbestos base paper two sided coatings: 20 parts of vinyl chloride-vinyl acetate copolymer emulsions (solid content 50%), 5 parts of polyvinyl alcohol (PVA), 2 parts in sodium chloride, 8 parts in sodium sulphate, 3000 parts in water.Dry back is coated with precoat in the front, and filling a prescription is 30 parts of polyvinyl alcohol (PVA), 20 parts of polyvinyl acetate (solid content 47%), 5 parts in sodium sulphate, 48 parts of porcelain earth, 8 parts of talcum powder, 500 parts in water.Dry after super calendering, photosensitive coated layer in the above again, filling a prescription is: 100 parts on photosensitized oxidation zinc, 30 parts of 154 acryl resins, 0.1 part of rose bengal, 30 parts of toluene.Make electrostatic offset plate V0=350 volt, (V0-V30)/V0=50%, E1/2=50 lux second, the Vr=40 volt is split 1300 of space of a whole page printing numbers on offset press.

Reference examples two:

Go up photosensitive coated layer at photograph barium base stock (contains sodium sulfate, sodium chloride, barium sulphate, gelatin etc.), prescription makes electrostatic offset plate V0=450 volt with reference examples one, (V0-V30)/and V0=25%, E1/2=40 lux second, the Vr=25 volt is split 800 of space of a whole page printing numbers on offset press.

Claims (5)

1, a kind of zinc oxide electrostatic offset plate, by paper substrate, conductive layer stops tack coat, photographic layer and back-protective layer constitute, and it is characterized in that using in conductive layer titanate esters or silane coupling agent and alkaline metal salt; Use quaternary ammonium salt cation surfactant or alkyl sulfonate type anionic surfactant overleaf in the protective seam; In stopping tack coat, use the inorganic powder of metal halide and alkaline earth oxide; In photographic layer, use the polar material of organo silane coupling agent and hydroxyl.

2, conductive layer according to claim 1 is characterized in that coupling agent adopts titanate esters, as KR-138S, and TA-9, TCP-114 etc., or silane coupling agent, as KH-550, A-150, A-171 etc. or both combinations, shared amount is the 0.01-5% of metallic salt, preferably 0.1-0.5%.Alkaline metal salt has sodium sulphate, sodium chloride, and lithium chloride, aluminium sulphate etc., the concentration of metallic salt aqueous solution (concentration expressed in percentage by weight) is 0.1-10%, preferably 0.8-2%.

3, back-protective layer according to claim 1 is characterized in that ionic surfactant adopts the alkyl sulfonate anionic, as sodium dodecylsulphonate, and neopelex, right-ABPS; Also can adopt quaternary amines salt cationic, as ten people's alkyl-dimethyl hydroxyethyl quaternary amine nitrate, the hexadecyldimethyl benzyl ammonium ammonium bromide, trihydroxyethyl methyl quaternary amine Methylsulfate, its consumption is the 0.05-5% of resin, preferably 0.1-2%.

4, the tack coat that stops according to claim 1 is characterized in that the metal halide salt has sodium sulphate, sodium chloride, sodium sulphite, lithium chloride, bismuth iodide, cuprous iodides etc., its concentration are 0.005-1%, preferably 0.01-1%, the inorganic powder of alkaline earth oxide has potter's clay, porcelain earth, lime carbonate, titanium dioxide, its consumption is the 10-300% of resin, preferably 50-100%.

5, photographic layer according to claim 1 is characterized in that adopting organosilicon, the polar material of silane coupling agent and hydroxyl.Organosilicon such as fluorosioloxane rubber, room curing silicon rubber, dimethyl silicone polymer, the polyphenyl methylsiloxane, transparent silicon resin, organosilicon epoxy resin, consumption are the 5-300% of weight resin.Silane coupling agent has the r-r-chloropropyl trimethoxyl silane, vinyl ('beta '-methoxy ethoxy) silane, and γ-aminopropyl Ethoxysilane, consumption are the 0-5% of zinc paste weight, preferably 0.01-0.3%.The polar material of hydroxyl such as ethanol, water, ethylene glycol, glycerine, consumption are the 0.5-10% of solvent total amount, usual amounts is 2-6%.