JPH02276841A - Orientated film - Google Patents

Abstract

PURPOSE:To obtain an orientated film suitable as synthetic paper, having excellent heat resistance by blending a polyolefin resin with thermoplastic polyester and maleic anhydride modified or glycidyl methacrylate modified polyolefin resin. CONSTITUTION:(A) 95-55wt.%, preferably 80-60wt.% polyolefin resin (preferably polypropylene resin) is blended with (B) 5-45wt.%, preferably 20-40wt.% thermoplastic polyester resin (preferably polyethylene terephthalate) and (C) 1-50wt.%, preferably 2-35wt.% based on total amounts of the components A and B of a maleic anhydride modified polyolefin resin and/or glycidyl methacrylate modified polyolefin resin having >=0.01, preferably 0.1-10wt.% modified amount, molded into a sheetlike form and uniaxially or biaxially stretched at a temperature lower than the melting points of the component A and B to give an orientated film.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an oriented film, and particularly to an oriented film with excellent heat resistance suitable for use as synthetic paper. It does not shrink and is strong, so it will not curl even when heat is applied during printing, and can be used for printing papers such as art paper and poster paper.
It can be used as information paper such as computer form paper, electrostatic recording paper, and base material sheets for image-receiving sheets for thermal transfer recording, and in particular, it can be used as a bar that forms characters and images on the receiving surface using electrical signals such as laser beams and thermal heads. It is useful as a support for color copying used in coded paper, video printers, etc.

[Prior Art] Conventionally, in image-receiving paper for thermal transfer recording, a transfer member having a transfer layer containing a sublimable or vaporizable dye and a receiving paper are placed on top of each other, and this transfer member is heated during printing. Thermal transfer was performed by sublimating or vaporizing the dye contained in the transfer layer and dyeing the receiving paper to form a dye image on the receiving paper.

Specifically, in a transfer type thermal recording method using a heat source controlled by an electric signal such as a thermal head, as shown in FIG. An image receiving paper 1 having a support 1a and a support 1a is transferred to a drum 3.
and the heat source 4, and the coloring material layer 2 is applied in response to an electric signal.
A color copy is obtained by heating the coloring material b and transferring it onto the image-receiving layer ib.

The material used for the image-receiving layer tb differs depending on the content of the coloring material used. In the case of a heat-melting coloring material containing a pigment, the support 1a itself may be used; In the case of a coloring material, an activated clay layer is used, and in the case of a sublimable disperse dye type coloring material, a coating layer of a polymeric material such as a polyester latex solution is used.

Further, as the support 1a, pulp paper, synthetic paper made of a stretched oriented film of thermoplastic resin containing 8 to 65% by weight of inorganic fine powder (see Japanese Patent Publication No. 46-40794), transparent stretched oriented polyethylene Coated synthetic paper is used, which is made by coating the surface of terephthalate film or transparent polypropylene film with an inorganic compound such as silica or calcium carbonate together with a binder to improve whiteness and dyeability.

However, after-use of thermally transferred image receiving paper 1 (
(copying, pencil writability, storage stability, etc.), it is recommended to use a polyolefin resin film containing inorganic fine powder as the image-receiving paper for thermal transfer recording in terms of strength, dimensional stability, and adhesion to the print head. Synthetic paper with many microvoids inside obtained by stretching is preferred (Japanese Unexamined Patent Publication No. 1983
-245593, 61-112693, patent application No. 6
(See Publication No. 2-25080).

[Problems to be Solved by the Invention] Such polyolefin resin-based synthetic paper is made of polyolefin as a material in order to provide opacity and a soft feel, as well as to improve adhesion to the print head and paper feeding/ejection properties. The film is stretched at a temperature lower than the melting point of the resin to form microvoids inside.

However, the polyolefin resin has a melting point of 167
℃ or less, polyethylene terephthalate (240~25
On the other hand, the surface temperature of the receiving paper during printing by the print head is 190-200°C, which is higher than the above melting point, albeit for a short period of time. It has been pointed out that the synthetic paper shrinks due to heat, and the receiving paper on which heat-sensitive transfer is applied curls on the printed inner surface (JP-A-60-245593, JP-A-60-245593, No. 61)
(Refer to Publication No.-283595).

A molecularly oriented polyester resin film containing an opaque or translucent two-wheel stretched olefin polymer with excellent heat resistance is known (Japanese Patent Application Laid-Open No. 57-49648).
However, although this molecularly oriented polyester resin film has excellent heat resistance, because the amount of olefin polymer blended with the polyester resin is too small, There are problems in that it lacks a soft feel and is not necessarily sufficient in terms of adhesion with the print head, paper feeding and ejection properties, etc.

Means for Solving Problem E] The present inventors have conducted extensive research in view of the above problems, and have found that the main component is a polyolefin resin, a small amount of a polyester resin is blended therein, and a specific compatibilization method has been developed. The present inventors have discovered that the above object can be achieved by incorporating an appropriate amount of the agent, and have completed the present invention.

That is, the present invention includes (A) component: at least one polyolefin resin 95
~55% by weight, +B] component: a small amount (both 5 to 45% by weight of a type of thermoplastic polyester resin, (C) component: maleic anhydride-modified polyolefin resin or glycidyl with a maleic anhydride modification amount of 0.01% by weight or more) Modified polyolefin resin selected from glycidyl methacrylate modified polyolefin resins having a methacrylate modification amount of 0.01% by weight or more 1 to 50% by weight based on the total amount of (A) and f8) above
.

The present invention provides an oriented film characterized by comprising:

[Detailed Description of the Invention 1 (1) Constituent Components The oriented film of the present invention comprises (A) a polyolefin resin;
It is basically composed of (B) polyester resin and (C1) maleic anhydride-modified polyolefin resin or glycidyl methacrylate-modified polyolefin resin, and this paper is different from conventional synthetic paper made of polyolefin resin containing inorganic fine powder in terms of opacity, whiteness, and wind resistance. It is similar in terms of texture and feel, and can be used as synthetic paper in itself.Furthermore, the polyester resin contained in a small amount in the film forms a backbone, giving the film itself heat resistance and stiffness. has been granted.

Component (A): Polyolefin resin Examples of the polyolefin resin used in the oriented film of the present invention include polyethylene, polypropylene, and polyolefin resin.
In addition to low-density and high-density olefin homopolymers such as J (4-methylpentene-1), olefin copolymers based on olefins and different types of monomers or mixtures of olefins (e.g. ethylene-propylene copolymers, ethylene-acetic acid (vinyl copolymer) can be used. The copolymers may be random, block or graft copolymers; it is also possible to use mixtures of olefin homopolymers and/or olefin copolymers. Among these, polypropylene resin is preferred in terms of heat resistance, solvent resistance, and cost.

In the polyolefin resin of component (A), polystyrene, polyamide, partial hydrolyzate of ethylene/vinyl acetate copolymer, ethylene/acrylic acid copolymer, and Salts thereof, vinylidene chloride copolymers such as vinyl chloride/vinylidene chloride copolymers, etc. may be blended.

The amount of polyolefin resin blended into the crystal oriented film of the present invention is 95 to 55% by weight in the oriented film.
, preferably within the range of 80 to 60% by weight.

(Bl component: polyester resin The thermoplastic Bossester resin used in the oriented film of the present invention contains one or more dicarboxylic acids or lower alkyl diesters thereof, such as terephthalic acid, isophthalic acid, 2.5-, 2.6- or 2.7-naphthalene dicarboxylic acid, cohelic acid, sebacic acid, adipic acid, azelaic acid, biphenyl-4,4'-dicarboxylic acid, hexahydroterephthalic acid, bis-p-carboxyphenoxyethane, etc., and one or more thereof. The above glycols, such as ethylene glycol, 1,3-propanediol,
It can be produced by condensation with neopentyl glycol, 1,4-cyclohexane dimetatool, etc. A preferred polyester resin is polyethylene terephthalate.

The polyester resin used in the present invention may be a copolymer containing mixed hydroxyl groups and/or ester-forming acid groups, or may be a block copolymer consisting of different polyesters. Such copolyesters include: The polymer used for this polymerization segment may contain a polymerization segment with a glass transition temperature lower than O'C so that the polyester resin is internally plasticized. Particularly suitable polymerizable segments are polyethylene glycols and tetramethylene glycols, which must be capable of polycondensation with the polyester segments by means of groups, or can be attached to the polyester segments by the use of chain extenders; Typically polyethylene terephthalate or polybutylene terephthalate.

The amount of polyester resin blended into the oriented film of the present invention is 5 to 45% by weight in the oriented film.

Preferably it is within the range of 20 to 40% by weight.

fcl component: maleic anhydride-modified polyolefin resin and/or glycidyl methacrylate-modified polyolefin resin The maleic anhydride-modified polyolefin resin used in the oriented film of the present invention has a maleic anhydride modification amount of 0. The glycidyl methacrylate-modified polyolefin resin is a glycidyl methacrylate-modified polyolefin resin with a glycidyl methacrylate modification amount of 0.01% by weight or more.

Such a modified polyolefin resin can be obtained by graft copolymerizing maleic anhydride or glycidyl methacrylate to the polyolefin resin of the fAl component.

In order to graft copolymerize maleic anhydride or glycidyl methacrylate to a polyolefin resin, the polyolefin resin is dissolved or suspended in a solvent,
After adding the grafting monomer maleic anhydride or glycidyl methacrylate, the radical generator is added little by little at the decomposition temperature of the radical generator, generally 50 to 150°C, and the graft reaction is carried out, or the grafting monomer is added to the polyolefin resin. Graft polymerization is carried out by heating a certain maleic anhydride or glycidyl methacrylate in an extruder at 150 to 260° C. using a radical generator.

The modified polyolefin resin thus obtained contains 0.01 maleic anhydride units in the case of a maleic anhydride modified polyolefin resin.
% by weight or more, preferably from 0.1 to 1% by weight, and in the case of glycidyl methacrylate-modified polyolefin resins, glycidyl methacrylate units in an amount of % by weight or more, preferably from 0.1 to 10% by weight. included in.

Such modified polyolefin resin is blended in an amount of 1 to 50% by weight, preferably 2 to 35% by weight, based on the total amount of components (A) and (B).

(2) Formation of oriented film After blending the above (Al, (Bl) and (C1 components) and forming into a sheet, the crystals are oriented by stretching in the uniaxial or biaxial direction at a temperature lower than the melting point of the polyolefin or polyester resin. The oriented film of the present invention is obtained by the following steps. During stretching, microvoids (small pores) are generated between the polyolefin and polyester polymers, and the film becomes translucent or opaque. Density is 0.75-0.90g/c+w
1 has excellent lightness.

(3) Thermal transfer image-receiving paper Thermal transfer image-receiving paper 1 in which an image-receiving layer 1b was formed by applying a coating solution for forming an image-receiving layer on the surface of the oriented film la of the present invention and drying to scatter the solvent. can be manufactured.

(Image-receiving layer) As the resin forming the image-receiving layer 1b, oligoester acrylate resin, saturated polyester resin, vinyl chloride/vinyl acetate copolymer, acrylic ester/styrene copolymer, epoxy acrylate resin, etc. are used. These are dissolved in toluene, xylene, methyl ethyl ketone, cyclohexanone, etc. and used as a coating liquid.

This coating liquid can contain an ultraviolet absorber and/or a light stabilizer to improve light resistance.

Further, in order to improve the mold releasability from the thermal transfer member 2, a mold release agent can be contained in the image receiving layer lb.

Further, the whiteness of the image-receiving layer 1b is improved to further enhance the clarity of the transferred image, as well as to impart writability to the surface of the thermal transfer sheet l, and to prevent the transferred image from being re-transferred. A white pigment can be added to the receiving layer tb.

The thickness of the image receiving layer 1b is generally 0.2 to 2011I11.

[Example] The present invention will be explained in more detail with reference to Examples below.

Examples 1 to 8, Comparative Examples 1 to 9 Original sheet molding (Al component: polypropylene (pp), F81 component: polyethylene terephthalate (PETI or polybutylene terephthalate [PBT)] and (C1 component: maleic anhydride as modified polyolefin resin) (LIAIll grafted polypropylene or glycidyl methacrylate (GMAI) Each resin composition blended with craft polypropylene in the proportions shown in Table 1 was melt-kneaded using an extruder and extruded into a sheet form from a die at a temperature of 260°C. It was immediately cooled to a temperature of 80°C using a cooling roll to obtain a sheet with a thickness of 2 mm.

From the original fabric sheet obtained by stretching processing, 120m+ x 120m
A test piece cut out into a square of m square was heated to the following tAl or (131
A blended film was obtained by stretching under the following conditions.

On the oriented film la obtained in the examples and comparative examples,
An image-receiving layer-forming composition having the following composition was applied by Mayer coating to a dry thickness of 41 m, and dried to form an image-receiving layer 1b to obtain an image-receiving paper 1 for thermal transfer recording.

Saturated polyester (Toyobo Byron 2007g 67°C) 5.3 parts by weight (
〃 Vylon 290 Tg 77°C) 5.3 parts by weight Vinyrite VYHH (vinyl chloride vinyl acetate copolymer manufactured by Union Carbide) 4.5 parts by weight Titanium oxide (A-10 manufactured by Titan Kogyo) 1.5 parts by weight Amino-modified silicone oil (Shin-Etsu Silicon KF-393) 1.1 weight 1 part epoxy modified silicone oil (Shin-Etsu Silicon '%X-22-343) 1.1
Parts by weight Toluene 30 Parts by weight Methyl ethyl ketone 30 Parts by weight Cyclohexane 22 Parts by weight Physical properties such as stretching processability, density, opacity, tensile modulus, etc. of the films obtained in Examples and Comparative Examples and images produced from each oriented film Image evaluation of the receiving paper was performed using the measurement method shown below.

The results are shown in Table 1.

Stretchability: Stretchable (Film thickness: 100-150 un)
No: Unable to stretch. Measured using an 11 degree color difference meter (manufactured by Suga Shikenki ■).

Ushijke11 Kei It was measured using Tensilon (■ manufactured by Orientic).

Tensile speed: 200 mm/min. When the synthetic paper is placed on a flat surface without being fixed and left at a temperature of 120°C for 30 minutes, the dimension l is determined as 1 l l l, and the original length i. The difference between this value and 1 was determined, and the heat shrinkage rate was determined using the following formula.

Image receiving paper 1 for thermal transfer recording and transfer film ``TTF Cyan'' (trade name) made by Mitsubishi Paper Industries, which has been coated and dried with a sublimable dye as transfer material 2, are superimposed and tested using a thermal gradient tester (Toyo Seiki'!ff1Type-HG). -100), the hot plate was heated at 5 points at 10°C intervals from 120°C, and 0.5
A transferred image was obtained by heating for 2 seconds at a pressure of "kg/cm".

The density of the resulting transferred image was measured using a Macbeth densitometer and evaluated on the following five scales.

5: Very good 6 4: Good.

3: No practical problem.

2: There are some practical problems.

l: Not practical.

[Brief explanation of drawings]

FIG. 1 shows a sectional view of an oriented film according to an embodiment of the present invention, and FIG. 2 shows a sectional view of a main part of a transfer thermosensitive recording device. ■: Image receiving paper for thermal transfer recording, 1a: Oriented film 1b Two image receiving layers 2: Transfer body
2a 2 substrates 2b = transfer layer 3 Ni drum 4: heat source

Claims (1)

[Claims] (1) An oriented film comprising the following components (A), (B), and (C). (A) Component: At least one polyolefin resin 95
~55% by weight, component (B): 5~45% by weight of at least one thermoplastic polyester resin. Component (C): Modified polyolefin resin selected from maleic anhydride-modified polyolefin resins having a maleic anhydride modification amount of 0.01% by weight or more or glycidyl methacrylate-modified polyolefin resins having a glycidyl methacrylate modification amount of 0.01% by weight or more. 1 to 50% by weight based on the total amount of (A) and (B).