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
  • G03C1/795—Photosensitive materials characterised by the base or auxiliary layers the base being of macromolecular substances
  • G03C1/7954—Polyesters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M1/00—Inking and printing with a printer's forme
  • B41M1/26—Printing on other surfaces than ordinary paper
  • B41M1/30—Printing on other surfaces than ordinary paper on organic plastics, horn or similar materials
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
  • C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds

Definitions

• a synthetic sheet for writing and like other purposes which consists essentially of a linear polyester and a high polymer having a higher glass transition point than that of the linear polyester at a rate of 7 to 35% by weight of the latter with respect to the total polymer mixture.
• a method for producing a synthetic writing sheet which comprises mixing a linear polyester resin and a polymer having a higher glass transition point than that of the polyester resin, forming the mixture into a film, and stretching the film at a temperature above the glass transition point of the linear polyester but below the melting point thereof.
• the linear polyester to be used in the present invention designates polyethylene terephthalate, polyethylene isophthalate, copolymer of ethylene terephthalate and ethylene isophthalate, and so forth.
• example is between 69 C. and 70 C. (in the case of organic fine particles having a size ranging from a few to several tens of microns over the entire surface of the film;
• polyester film is ordinarily formed by melt-extrusion after the material is desiccated, as the inorganic fine particles added to the resin material remain, in most cases, in the drying chamber as well as in crystalline polyethylene terephthalate, it is 81 C.).
• the high polymers having higher glass transition point than that of the polyethylene terephthalate are: acrylic polymers such as, for example, polymethylmethacrylate, copolymers of acrylouitrite and styrene, copolymers of acrylonitrile, butadiene, and styrene; polymers of styrene such as polystyrene; and carbonate copolymers such as 4,4-dihydroxydiphenyl-2,2 propane carbonate, etc.
• the quantity of the high polymer to be added to the linear polyester depends on the kind of the polymer. A preferable range is between 7% by weight and 35 by weight of the total polymer mixture. Even when the mixing quantity of the polymer is small, the stretched film becomes semitransparent, although no proper wri-tability can be attained. On the contrary, if the mixing quantity of the high polymer is excessive, the resulting film, when it is stretched, is easily breakable and becomes diflicult to attain adequate stretching. Also, the rupture strength of the film becomes low when the stretching is carried out at a temperature lower than the glass transition point of the linear polyester. When the film is stretched at a temperature higher than the melting point of the linear polyester, the molecular chain of the polyester becomes fluidized with the result that the film does not orientate and no stretch effect can be recognized.
• Forming, into film of the mixed polymer materials may beresorted ,to by thev ordinary method, for forming the linear polyester such as melt-extrusion by T-die or annular die. r I 1 .
• the thus formed film is subjected to either sequential or simultaneous stretching. Stenter method, and tubular stretching method areusually employed. The stretching temperatureand the stretch ratio are also governed by the high polymer to be added to the linear polyester.
• the writability and opacity of the writing sheet according to the present invention can be first realized by the stretching, the reason for which is as follows.
• the glass transition point of the amorphous polyethylene terephthalate is from 69 C. to 70 C. (81 C. in crystalline state).
• a high polymer having a glass transition point higher than that of polyethylene terephthalate is mixed with the polyethylene terephthalate, formed into film, and stretched at a stretching temperature above the glass transition point of the polyethylene terephthalate and below the melting point thereof, polyethylene terephthalate assumes a rubbery state, while the high polymer added thereto is in glassy or rubbery state depending on its kind.
• polyethylene terephthalate is more preferentially stretched than the high polymer, and oriented in the vicinity of the high polymer with it as nucleus to produce irregularity on the film sur- .face, Moreover, where both polymers are dispersed uniformly, the surface irregularity of the film becomes extremely fine with the consequence that very ideal mat surface capable of producing good writing, uniform thickness of drawing lines adhered onto the sheet surface and appropriate opacity can be obtained.
• the mixing high polymer may or may not have compatibility with the linear polyester, provided that it can be substantially uniformly mixed with and dispersed in the linear polyester at the time of forming, and that the formed film, regardless of whether it is transparent or not, may produce a uniform mat surface upon being stretched. It is, however, more desirable that the mixing high polymer be compatible with the linear polyester and the melting point'of both polymers be as close to each other as possible, which facilitates film forming operation.
• the film thus obtained is heat-shrinkable, excellent in its writability, and possesses adequate opacity.
• ther improve stability in the film size at a high temperature, it may be heat-treated at a temperature above the stretching temperature of the linear polyester and below the melting point of both mixing high polymer and the linear polyester.
• the writing sheet according to the present invention is useful not only for writing and copying alone, but also for various purposes such as decoration paper, metal-plated paper, labels, stickers, and various other indications, as well as wrapping paper. It is particularly worthy of note that, as this writing sheet has a hardened surface by the combination of the abovementioned two sorts of polymers alone without use of any inorganic filling agent, which sur- .face is adapted to inscription with pencil of comparatively high hardness and writing ink, and given adequate opacity, and its physical properties such as rupture strength, etc. are satisfactory as aforementioned, it is best used as drawing paper.
• the raw material is composed of the linear polyester and the thermoplastic polymer it is uniformly melted when it is melt-extruded into film, which enables film forming operation as readily as in the case of film forming from an individual polymer material. No inconvenience in the film forming which is liable to take place due to unmelted, non-fiuidizing substance occurring in the case of adding fine particles of inorganic substance is caused. Nor, there is no problem at all with the preliminary treatments such as drying, etc. to be done in ad- Vance of the film forming operation.
• films of various sorts can be manufactured .freely by a single unit of extruder Without accompanying difiiculty in change over from one kind of polymer material to another, and the film thickness can be arbitrarily regulated, which contribute to increase in productivity, reduction in manufacturing cost, stable supply of the product to the consumer, and other remarkable effects.
• EXAMPLE 1 Polymethyl methacrylate of varying quantities was mixed with polyethylene terephthalate, and the mixture was subjected to melt-extrusion through a T-die to form sample films of 150 microns thick of different compositional ratio. These film samples were heated to a temperature of 90 C. in a biaxial stretching machine, and then simultaneously stretched in both longitudinal (lengthwise) as wellas transverse (widthwise) directions of the film TABLE 1 Polymethyl methacrylate/polyethylene terephthalate (percent by weight) f Up to 311 hardness.
• EXAMPLE 2 p A copolymer of acrylonitrile and styrene was mixed with polyethylene terephthalate at a given ratio, and the mixture was formed into film samples of 150 microns by axial stretching machine in both longitudinal and transverse directions thereof at different temperatures and stretch ratios.
• EXAMPLE 3 General purpose (GP) polystyrene was mixed with polyethylene terephthalate at different ratios, and the mixture was formed into film samples of 150 microns thick by the melt-extrusion through the T-die. These specimen films were stretched in their longitudinal direction alone by a biaxial stretching machine at 90 C. and at a stretch ratio of 3.5 times.
• Flaky polycarbonate composed of bisphenol A was mixed with polyethylene terephthalate at varying ratios given below, and the mixture was formed into film samples of microns thick by the melt-extrusion through the T-die. These specimen films were stretched by a bi- 75 1. With the polycarbonate content of 5 wt. percent, the writability and haze value are poor. The film containing 50% of polycarbonate was not rendered uniformly opaque.
• a synthetic sheet for writing purposes which consists essentially of a linear polyester selected from the group consisting of polyethylene terephthalate, polyethylene isophthalate, and copolymers of ethylene terephthalate and ethylene isophthalate, and a high polymer having a higher glass transition point than that of said linear polyester at a mixing ratio of from 7 to 35% by weight of the latter with respect to the total polymer mixture, which high polymer is selected from the group consisting of a polymethylmethacrylate, a copolymer of acrylonitrile and styrene, a copolymer of acrylonitrile, butadiene, and styrene, and polystyrene, said synthetic sheet having a very finely coarsened surface due to said high polymer which is uniformly dispersed in said linear polyester to constitute the nuclei for the irregular surface thereof.
• a synthetic sheet according to claim 1 wherein the high polymer is polymethylmethacrylate.
• a synthetic sheet according to claim 1 wherein the high polymer is a copolymer of acrylonitrile and styrene.
• a synthetic sheet according to claim 1 wherein the high polymer is a copolymer of acrylonitrile, butadiene and styrene.

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Medicinal Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Physics & Mathematics (AREA)
• Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Compositions Of Macromolecular Compounds (AREA)

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Family Applications (1)

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Cited By (11)

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• 1970
  • 1970-05-26 JP JP45044521A patent/JPS4814657B1/ja active Pending
• 1971
  • 1971-05-24 US US00146446A patent/US3755499A/en not_active Expired - Lifetime
  • 1971-05-25 DE DE19712125913 patent/DE2125913A1/de active Pending
  • 1971-05-25 NL NL7107188A patent/NL7107188A/xx unknown
  • 1971-05-25 GB GB1694671A patent/GB1344522A/en not_active Expired
  • 1971-05-25 LU LU63219D patent/LU63219A1/xx unknown
  • 1971-05-26 FR FR7119083A patent/FR2090305B1/fr not_active Expired

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