Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/76—Photosensitive materials characterised by the base or auxiliary layers
  • G03C1/775—Photosensitive materials characterised by the base or auxiliary layers the base being of paper
  • G03C1/79—Macromolecular coatings or impregnations therefor, e.g. varnishes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/25—Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/3154—Of fluorinated addition polymer from unsaturated monomers
  • Y10T428/31544—Addition polymer is perhalogenated
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31855—Of addition polymer from unsaturated monomers
  • Y10T428/31909—Next to second addition polymer from unsaturated monomers
  • Y10T428/31913—Monoolefin polymer

Definitions

• the invention relates to a support material for photographic layers consisting of a paper or film material coated on one or both sides with polyolefin resin by means of melt extrusion coating.
• Polyolefin-coated photographic support materials usually consist of a sized base paper with waterproof polyolefin resin layers preferably applied on both sides.
• the polyolefin resin layers consist of polyethylene and are applied to the paper by means of extrusion coating (J. Appl Photographic Engineering 5th (1979) pp. 110-117).
• One or more photographic layers are then applied to one of the polyolefin resin layers (front side layer) after a pretreatment of the layer surface which is necessary for promoting adhesion.
• These photographic layers can be those for black / white as well as for color photography with associated auxiliary layers.
• the front layer usually contains light-reflecting white pigment, preferably a titanium dioxide and, if appropriate, color pigments, optical brighteners and other additives such as dispersants for the pigments, release agents, lubricants, anti-oxidants, antistatic agents or the like.
• the synthetic resin layer (back layer) arranged on the paper side opposite the light-sensitive layers is preferably not pigmented. However, it can also contain pigment and other additives which result from the use of the coated paper as a photographic support material and which can in principle correspond to those of the front layer.
• Additional functional layers can be located between the front layer and the actual photographic layers, which, for example, improve the adhesion of the photographic layers or perform another function due to the use of the material.
• the back layer can also be covered with further functional layers which improve, for example, the writeability, the conductivity, the adhesiveness, the flatness or other properties of the carrier material.
• the procedure for polyolefin coating is usually such that the front layer consists predominantly of a lower density polyolefin (e.g. LDPE), while the back layer mainly consists of a higher density polyolefin (e.g. HDPE).
• LDPE lower density polyolefin
• HDPE higher density polyolefin
• the coating of photographic base papers with polyolefin is generally done as a melt coating with the aid of extrusion coating systems with a slot die. This process is known both as a single coating process and as a multiple coating process. Auxiliary layers and additional functional layers can be applied with the aid of all known coating methods both in separate coating systems and "in line" with the extrusion coating (EP 21749).
• the design of photographic support materials is determined in various ways by taste considerations. This applies, for example, to tinting both the base paper and the front layer with small amounts of dyes or color pigments. This also applies in a special way to the design of the surface of the front layer. Both high-gloss and matt and structured surfaces are known. The degree of roughness or the surface structure can be determined very precisely with the help of differently designed cooling rollers and can be tailored to different customer requirements.
• each coating process, as well as each coating material has specific advantages and disadvantages which are well known to the person skilled in the art and which lead him to decide on a case-by-case basis which process and which material is used in which combination for a specific photographic support material.
• the person skilled in the art is also aware that he must avoid certain additives which are customary in the plastics or paper industry, because they can react with constituents of the photographic layers and are therefore troublesome in photographic support materials and can even lead to the uselessness of the support material , while others are indispensable for the production of polyolefin resin coated substrates for photographic layers.
• the latter group includes, for example, white pigments such as preferably titanium oxides, colored pigments, dispersants for pigments, antioxidants, optical brighteners or some processing aids.
• Certain processing aids which are also known as lubricants or release agents, are added to most polyolefin coating compositions for photographic supports and are indispensable, in particular, for those coating compositions which are processed with the aid of a glossy cooling roller to form layers with a glossy surface.
• These release agents include stearic acid, glycerol stearates, metal salts of higher fatty acids or amides of higher fatty acids. Additions of magnesium stearate, zinc stearate, aluminum stearate or erucic acid amide are very common for polyolefin coated papers for photographic purposes. It is also known to use polyethylene glycol as a release agent in polyolefin coating compositions.
• release agents An important function of these release agents is to ensure that the extruded polyolefin film is separated easily and evenly from the chill roll. In the absence of such release agents, the detachment of the polyolefin film from the chill roll does not always occur uniformly but at short rhythmic intervals, and fine elevations are formed which run transversely to the web direction.
• These hair-fine surveys cannot be detected by conventional tactile methods for measuring the surface professional, but are clearly visible as fine lines on glossy surfaces in the case of oblique light incidence, which run parallel to one another and are at a distance of about 1 mm from one another. That is why they are also called “staff lines".
• the "staff lines” generally occur at coating speeds that are greater than 70-80 m / min and increase with increasing speed.
• release agent additive is roughly proportional to the coating speed, i.e. higher coating speeds require higher amounts of release agent. Amounts between 0.5 and 1 wt .-% based on the coating composition are quite common.
• lubricants or release agents are associated with disadvantages.
• Release agents not only facilitate the detachment of the polyolefin film from the chill roll, but also weaken the adhesion of the polyolefin film to the base paper.
• the release agents perspire due to the high extrusion temperatures. The vapors partially condense on machine parts and the condensate can drip onto the web. In the worst case, greasy deposits form on the chill roll and are transferred from there to the polyolefin surface, where they are not only visible as gloss defects but also impair the formation and adhesion of photographic layers applied later.
• the object of the invention is therefore to provide a polyolefin-coated support material for photographic layers which does not have the disadvantages described.
• a coating speed of more than 100 m / min is considered to be an economically acceptable production condition
• the admixed fluorine-containing polymer is a polymer or copolymer of vinyl fluoride, vinylidene fluoride, trifluorochlorethylene or hexafluoropropylene, which contains 30-76% by weight of fluorine and is added in an amount of 40 to 1500 ppm to the polyolefin coating composition
• a further development of the invention is accordingly a material coated at least on one side with polyolefin, for example paper, the polyolefin coating of which contains a fluorine-containing polymer, a polymer which contains 30-76% by weight of fluorine and the polyolefin coating composition in an amount of 40 to 1500 being preferred ppm was added.
• polyolefin for example paper
• the polyolefin coating of which contains a fluorine-containing polymer, a polymer which contains 30-76% by weight of fluorine and the polyolefin coating composition in an amount of 40 to 1500 being preferred ppm was added.
• the backing paper for photographic layers on the polyolefin layer (front layer) adjacent to the photographic layer contains a polymer or copolymer of vinyl fluoride, vinylidene fluoride, trifluorochloroethylene or hexafluoropropylene in an amount of 40-1500 ppm.
• the invention further relates to a method for producing a polyolefin-coated support material for photographic layers by means of extrusion coating, which is characterized in that a fluorine-containing polymer is mixed in the form of a premix at least into the polyolefin coating composition used for coating the front side.
• the blended amount of fluorine-containing polymer is preferably 40-1500 ppm based on the polyolefin coating composition and is a polymer or copolymer with a fluorine content of 30 to 76% by weight.
• the base material coated with polyolefin according to the invention is preferably a photographic base paper which is internally sized in a known manner and has been given a surface size.
• the base material can also be a paper made of synthetic fiber material or film material.
• the polyolefin coating is carried out in a known manner by means of extrusion coating.
• One side of the material can have several polyolefin layers on top of one another.
• There may also be another layer under a polyolefin layer for example a conventional barite layer, a layer hardened with electron beams, an adhesion-promoting layer or a barrier layer, and further known layers may be applied to the polyolefin layer before a photographic layer is placed over it becomes.
• the fluorine-containing polymer is advantageously first kneaded into a premix containing 1-5% by weight of fluoropolymer with polyolefin, granulated and mixed in this form with the rest of the coating mixture before extrusion.
• the preferred polyolefin for the preparation of the premix is polyethylene, in particular a low-density polyethylene, so-called LDPE.
• the fluorine-containing polymer admixed according to the invention with the polyolefin mixture is preferably a polymer or copolymer of fluorine-containing monomers such as vinyl fluoride, vinylidene fluoride, trifluorochloroethylene or hexafluoropropylene.
• fluorine-containing monomers such as vinyl fluoride, vinylidene fluoride, trifluorochloroethylene or hexafluoropropylene.
• Other fluorine-containing monomers may also have been used in a minor amount to produce the polymer, for example a copolymer of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene is also suitable as an additive for layers according to the invention.
• the fluorine-containing polymer can also contain non-fluorine-containing monomers, for example ethylene, vinyl chloride, acrylic acid or others, in minor amounts.
• the molecular weight of the fluorine-containing polymer is variable in a wide range. Polymers with a molecular weight of 5,000 were used with good results as well as those with an average molecular weight of 500,000.
• the polyolefin resin layer which contains the fluorine-containing polymer is a white pigment-containing polyolefin layer.
• the white pigment is usually a rutile or anatase type titanium dioxide pigment or a mixture containing titanium dioxide with other white pigments.
• the white pigments used in extrusion coating compositions are generally those which have received an inorganic or organic or inorganic and organic surface treatment.
• the layer may contain small amounts of colored pigments, dispersing aids, optical brighteners, antioxidants or other additives known in connection with photographic supports.
• the polyolefin layer contains a release agent combination consisting of the fluorine-containing polymer and a polyether glycol.
• the polyether glycol is a polyethylene glycol with a molecular weight between 200 and 35,000 or a polypropylene glycol with a molecular weight between 400 and 10,000 or an ethylene oxide / propylene oxide copolymer with a molecular weight between 400 and 30,000.
• the amount of used Polyether glycol is between 10 and 500 ppm based on the complete coating mixture.
• Polyolefin coating compositions according to the invention with an addition of fluorine-containing polymer show clear processing advantages in comparison with all previously known mixtures.
• Fatty acid derivatives as release agents are unnecessary and, if desired, a matt and glossy surface can be produced without quality-reducing exudation and without the dreaded "score lines".
• the adhesion to the paper or film base is unexpectedly not deteriorated, but is even slightly improved, and in spite of the incompatibility of the fluorinated polymer with the polyolefin resin, no inhomogeneities are observed in the extruded film.
• Magnesium stearate which is occasionally present in polyolefin mixtures as a dispersant for pigment or as a neutralizing component for catalyst residues, is tolerated without disadvantages, especially since it is present in amounts which remain below 0.3% by weight.
• the undesired fatty acid amides and fatty acid esters can be completely dispensed with, and fatty acid salts are also superfluous for reasons of separation.
• the result is particularly surprising because the separation of the polyolefin mixture from the chill roll is easy and without residue formation, but the adhesion between the substrate and the coating is even improved.
• the adhesion of the photographic layers to a polyolefin layer containing fluorinated polymer according to the invention is also not impaired.
• polyolefin resin used for the extrusion coating There are no particular restrictions on the polyolefin resin used for the extrusion coating. All polyolefin resins already described for extrusion coating with a slot die can be used, provided their melt index is between 1 and 35 g / 10 min. This can be polyethylene (HDPE, LDPE, LLDPE), polypropylene, ionomer resin or another olefin copolymer resin. It is crucial that the resin is suitable for the melt coating process and that the layer produced is no longer adhesive after cooling. The invention is illustrated by the following examples.
• the photo base paper from Example 1 was coated on the back as in Example 1.
• the front was coated with 30 g / m 2 of the following mixtures, a glossy surface being given to these coatings by means of a high-gloss cooling roller:
• the length of the web is indicated, which could be coated without any problems, before cleaning measures have to be taken due to the formation of condensate, cooling rollers or matt spots on the glossy surface of the coated base pair.
• the cooling water temperature of the cooling roll was +10 ° C.

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• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Physics & Mathematics (AREA)
• Laminated Bodies (AREA)
• Paper (AREA)
• Light Receiving Elements (AREA)
• Physical Vapour Deposition (AREA)
• Paints Or Removers (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

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ID=6330029

Family Applications (1)

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• 1987
  • 1987-06-20 DE DE19873720518 patent/DE3720518A1/de active Granted
• 1988
  • 1988-02-11 DE DE8888101988T patent/DE3861067D1/de not_active Expired - Lifetime
  • 1988-02-11 EP EP88101988A patent/EP0298188B1/de not_active Expired - Lifetime
  • 1988-02-11 AT AT88101988T patent/ATE58439T1/de not_active IP Right Cessation
  • 1988-02-11 ES ES88101988T patent/ES2018701B3/es not_active Expired - Lifetime
  • 1988-02-29 AU AU12385/88A patent/AU605556B2/en not_active Ceased
  • 1988-03-30 JP JP63074879A patent/JP2721172B2/ja not_active Expired - Lifetime
  • 1988-05-11 CN CN88102789A patent/CN1016382B/zh not_active Expired
  • 1988-05-23 US US07/197,454 patent/US5004644A/en not_active Expired - Fee Related

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