JPH01136783A - Printing base material for printer - Google Patents

Abstract

PURPOSE:To prevent a curling deformation from occurring at the time of printing, by melt-extruding polyethylene terephthalate chips containing a specified amount of white inorganic particles, and biaxially stretching the extrudate to form a film having a cushion factor of 6-25%. CONSTITUTION:Polymerization of polyethylene terephthalate is carried out by adding 8-40wt.% of white inorganic particles, e.g., particles of titanium oxide, calcium carbonate, calcium sulfate, barium sulfate or silica, to form chips containing the white inorganic particles. The polymer chips are melt- extruded, followed by biaxial stretching of the extrudate, by known means, to produce a printing base material for a printer having a cushion factor of 6-25%. The biaxial stretching is preferably carried out by a method wherein stretching in each of the two directions is carried out dividedly several times, whereby the cushion factor can be easily enhanced, and favorable suitability for printing can be ensured.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a printing base material for a printer.

[Prior Art] Conventionally, so-called paper or polypropylene-based printing substrates have been used as printing substrates for printers.

[Problems to be solved by the invention] However, in the above-mentioned conventional technology, the paper is easily torn, and the polypropylene-based white film has poor heat resistance, so when printed with a thermal transfer printer, the paper is easily damaged by the heat during printing. Curling occurs or the printed surface becomes wavy. As a means to improve these drawbacks, it is conceivable to use a biaxially stretched polyester film as the base material. However, when a biaxially oriented polyester film is used as a printing base material, printing properties are poor and the printing becomes unclear, and ink transfer is difficult, which causes so-called handling problems. In particular, video printers that require sharp images cannot be put into practical use because only unclear images can be obtained.

The object of the present invention is to solve these problems and provide a printing substrate for printers that uses polyester that has excellent strength and heat resistance, has excellent printing suitability during printing, and is free from curling.

[Means for Solving the Problems] The present invention is a film obtained by melt-extruding a polymer chip containing 8 to 40 wt% of white inorganic particles in polyethylene terephthalate and biaxially stretching the film, wherein the cushioning ratio of the film is The present invention relates to a printing base material for a printer, characterized in that the content is 6 to 25%.

Polyethylene terephthalate (hereinafter referred to as PE) according to the present invention
(abbreviated as T) means 8 ethylene terephthalate units.
The content is 0 mol% or more, preferably 90 mol% or more. Of course, within the above range, other types of dicarboxylic acid components (e.g., isophthalic acid, adipic acid, sebacic acid, etc.) or diol components (e.g., diethylene glycol, polyethylene gelcol, neopentyl glycol, etc.) may be copolymerized. Good too. Also, this PE
Various known additives such as antioxidants, lubricants, antistatic agents, etc. may be added to T.

White inorganic particles refer to well-known inorganic particles that are almost uncolored, and include titanium oxide, calcium carbonate, calcium sulfate, barium TiA acid, silica, alumina, talc, clay, etc., and the particle shape is oxidized. Granular materials such as titanium, calcium carbonate, and silica are preferred; talc,
Platy materials such as clay and needle-like materials such as asbestos tend to have poor printing suitability during printing. Moreover, the average particle diameter of these white inorganic particles is preferably 0.1 to 4 μm, more preferably 0.3 to 3 μm. If the average particle size is smaller than this range, the printing suitability during printing tends to be poor. On the other hand, if it is too large, the surface of the film becomes rough and the quality deteriorates. The white inorganic particles may be subjected to a dispersion treatment using stearic acid, sodium dodecylbenzenesulfonate, or the like. Moreover, two or more types of white inorganic particles may be mixed.

Among the white inorganic particles, calcium carbonate is most preferable from the viewpoint of dispersibility in PET, whiteness of the obtained film, stretching/film forming properties, and the like. Calcium carbonate may be either a natural product or a synthetic product, but any of these may be used.

In the present invention, such white inorganic particles are placed under PE.
The content is 40 wt%, preferably 12 to 35 wt%.

If the content is less than this range, it will be difficult to keep the cushioning ratio within the range of the present invention, and a printed substrate with excellent printing suitability will not be obtained. On the other hand, if there is too much, poor dispersion tends to occur.
Breakage occurs frequently during the stretching process, which is undesirable.

In the present invention, biaxial stretching refers to simultaneous or sequential two-wheel stretching according to a known method, and is necessary for imparting strength, heat resistance, etc. to the film. It is also necessary to improve the printing suitability during printing by imparting a printing rate.

The cushioning ratio in the present invention is a quantification of the change in thickness when a constant load is applied to the film.

In the present invention, the cushioning rate is 6 to 25%,
Preferably it is 8 to 20%. If the film is hard and the cushioning ratio is smaller than this range, the printing suitability during printing will not be improved. On the other hand, if the cushioning ratio is larger than this range, the surface will be too soft and will undergo plastic deformation, impairing the aesthetic appearance of the printed surface. Further, there is a problem that the film is easily broken during film formation and is difficult to manufacture, which is undesirable.

The whiteness of the film of the present invention is 70% or more, preferably 80% or more. If the whiteness is lower than this range, the contrast of printing will be poor and the appearance as a base material will also be impaired, which is not preferable.

Moreover, it is preferable that the thickness of the film of the present invention is 30 to 250 μm. If the thickness of the film is thinner than this range, it will be too stiff as a base material. - On the other hand, if it is thicker than this range, it is too hard and lacks flexibility.

Next, a method for manufacturing the film of the present invention will be described, but the method is not limited to this example.

The method for incorporating the white inorganic particles of the present invention into PET is preferably addition during polymerization. In addition, if white inorganic particles are treated with a surfactant or a phosphorus compound is added during polymerization,
The dispersibility of white inorganic particles is improved. If the dispersibility is poor,
Printability tends to be poor during printing, and the appearance tends to deteriorate. Furthermore, if the polymerization time or extrusion residence time is prolonged, the whiteness of the obtained film tends to be impaired, and the quality as a print base material is degraded. Next, the obtained polymer chip is melt-extruded and biaxially stretched by a known method, but it is preferable to perform the stretching in several stages in each axial direction, so that the cushioning ratio can be easily increased. The printing suitability during printing is improved. In order to impart heat resistance, flatness, etc. to the biaxially stretched film, 16
Heat fixation is performed at 0 to 230'C, and after uniformly cooling, it is cooled to room temperature and rolled up.

The film of the present invention can be obtained by setting appropriate manufacturing conditions as described above.

Further, the layer for receiving the ink to be printed can be formed on the film of the present invention by a known method such as barcode coating, reverse coating, gravure coating, etc.

[Measurement and evaluation method] (1) Dispersibility of particles in polymer 20 mg of Boria was sandwiched between two cover glasses,
After melt press cooling at 5°C, judgment was made by microscopic observation.

O: Almost no aggregated particles were observed. (This is within the objective range of the present invention) △: Slightly aggregated particles are observed (the objective of the present invention is not achieved) X: Many aggregated particles are observed. (The object of the present invention is not achieved) (2) Whiteness of film The whiteness was determined by JIS L1074 dual wavelength method 4B-3G.

◎: Whiteness 80% or more (particularly preferred within the objective range of the present invention) O: Whiteness 70% or more (preferable within the objective range of the present invention) X: Whiteness less than 70% (does not reach the objective of the present invention) ) (3) Cushion ratio Attach a 100 pedestal to the top of the spindle of a Mitoyo dial gauge, lift the spindle, and place it on the sample set on the measurement stand. Place a 50 CI weight on the pedestal, read the thickness after 5 seconds, and take the value at this time as 8 μm. Replace the weight on the pedestal with one of 5000, read the thickness after 5 seconds, take the value at this time as 5 μm, and use the following formula to calculate the cushion ¥? -C was shut out.

C=100x(a-b)/a (%) Note) Dial gauge type: No, 2109-10 Measuring point: 3mmφ hard ball (4) Printability during printing Shun coated with a 3μm ink receiving layer on the film, It was printed using a Sharp video printer GZ-P10B/W, and the print condition was observed and judged.

Q: The print and image are good and are preferred within the scope of the purpose of the present invention) X: The print and image are unclear or partially missing (the purpose of the present invention is not achieved) (5> After printing Curl deformation The printed film was placed on a flat plate, and the curl deformation was observed and determined.

O: Substantially no curl deformation (preferable within the objective range of the present invention) Now, one embodiment of the present invention will be explained.

Example 1 85 Wt parts of dimethyl terephthalate and 60 Wt parts of ethylene glycol were transesterified using 0.09 wt part of calcium acetate as a catalyst according to a conventional method, and then 10 parts of trimethyl phosphate was added as a phosphorus compound so that the amount was 0.25 wt% based on the polymer. ■ Add an ethylene glycol solution containing t%, and immediately add 40w of calcium carbonate with an average particle size of 1μ to the polymer to make it 18wt%.
t% ethylene gelcole slurry was added, and then 0.03 parts by weight of antimony trioxide was added as a polymerization catalyst.

Thereafter, a polycondensation reaction was carried out according to a conventional method under high temperature and reduced pressure to obtain polyethylene terephthalate having a local viscosity of 0.603. The dispersibility of calcium in the obtained polymer was good.

The obtained polymer was vacuum dried at 180'C for 4 hours,
It was fed to an extruder heated to 5°C to make an unstretched sheet, preheated with a group of rolls with a preheating temperature of 120°C and stretched twice, then longitudinally stretched to 2x at 115°C, for a total of 4x. 2
After being cooled in a group of rolls at 5°C, it was introduced into a tenter while holding both ends with clips, and preheated in an atmosphere of 85°C.
Stretched 1.7 times in an atmosphere at 95°C, then stretched at 115°C
After horizontally stretching 2 times and 3.4 times in total in an atmosphere of
A film with a thickness of 100 μm was obtained by heat setting at 220° C. The cushioning rate of this film was 13%.

On the obtained film, the following composition was barcoded as an ink receiving layer to a thickness of 3 μm (solid content) to obtain a printing film for a printer.

Polyester resin 10 parts by weight (Toyobo, Byron 200) Amino-modified silicone 0.5 parts by weight (F-393 manufactured by Shin-Etsu Chemical) Epoxy-modified silicone 0.5 parts by weight (X-22-343 manufactured by Shin-Etsu Chemical) Toluene /Methyl ethyl ketone-1 190 parts by weight The obtained printing film had good printing suitability during printing and was free from curling.

Examples 2 to 5, Comparative Examples 1 to 3 Printing films for printers were obtained in the same manner as in Example 1, except that calcium carbonate or the amount added thereof and the first stage stretching ratio were changed. The results are summarized in Table 1. These results show that by keeping the amount of white inorganic particles added and the cushioning ratio within the range of the present invention, a printing base material with good printing suitability during printing can be obtained.

Comparative Example 4 A biaxially stretched polypropylene film of 1q and 60 μm was curled by heating during printing using a conventional method.

Comparative Example 5 A commercially available printing substrate Sharp color video print sheet based on polypropylene also curled due to heating during printing.

[Effects of the Invention] The present invention produces a printing base material for printers in which multi-mouthed white inorganic particles are uniformly dispersed in PET and the cushioning ratio is within a specific range by biaxial stretching, so that the following excellent effects are achieved. It is something.

(a) A base material with excellent printability during printing can be obtained.

(b) A base material that does not undergo curl deformation due to heating during printing can be obtained.

Claims (2)

[Claims] (1) White inorganic particles in polyethylene terephthalate,
A printing base material for a printer, characterized in that it is a film obtained by melt-extruding and biaxially stretching a polymer chip containing 8 to 40 wt%, and having a cushioning ratio of 6 to 25%. (2) The printing substrate for a printer according to claim (1), wherein the white inorganic particles are calcium carbonate.