JPH05318575A - Stretched polyolefin film - Google Patents

Abstract

PURPOSE:To manufacture a stretched polyolefin film generating no unevenness or curing even when offset printing is applied by coating the single surface or both surfaces of a polyolefin film with a petroleum resin and subsequently stretching the coated film uniaxially or biaxially. CONSTITUTION:A stretched polyolefin film is produced by coating the single surface or both surfaces of a polyolefin film with a petroleum resin and stretching the coated film uniaxially or biaxially. By this constitution, even when offset printing is applied to the stretched polyolefin film thus produced, it can be prevented that the film becomes an uneven or curled state by the vehicle in offset ink. When curl height(h) is measured, for example, printed matter 1 is allowed to stand on the upper surface of a flat plate 2 for one day and the curl height(h) of the printed matter 1 is measured.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a uniaxially or biaxially stretched polyolefin having excellent printability, which prevents the film from becoming uneven or curled by the vehicle in the offset ink even when offset printing is performed. Regarding film.

[0002]

2. Description of the Related Art Lithography, which is generally called offset printing, can be easily used for multicolor printing and is therefore used for printing paper, polyethylene terephthalate film, polyamide, coated paper and the like. In particular, a general-purpose dry offset ink is composed of the compositions shown in Tables 1 and 2 below.

[0003]

[Table 1]

[0004]

[Table 2]

The above-mentioned vehicle is a liquid portion of the components constituting the printing ink, in which the pigment is dispersed to give fluidity to the ink, and on the printing machine, from the ink fountain to each roller, the plate,
Its function is to smoothly transfer to the printing surface via a blanket and to change to a solid after printing to fix the pigment to the printing surface. Linseed oil type, alkyd type, quick drying resin type, heat It is classified as a set type. In particular, in recent years, in order to improve the printing speed, it is required to shorten the drying time of the offset ink. Therefore, a resin and a mineral oil (high boiling point petroleum solvent) were mixed with a drying oil as a vehicle of the ink. Quick-drying ink is used. However, using these quick-drying offset inks, a synthetic paper made of a stretched product of a polyolefin film or a film containing inorganic fine powder in polyolefin (Japanese Patent Publication No. 46-40794, JP-A No. 61-279).
No. 543, No. 61-3748, etc.), the polyolefin is swollen by the vehicle (particularly high boiling point petroleum solvent such as mineral oil) of the offset ink used for quick-dry offset printing. When unevenness is partially generated on the surface of the printed film, or when printing is performed on the entire surface of the film, so-called solvent attack occurs, such as curling of the entire film, so it is difficult to actually use was there. Therefore, as the offset printing ink for a polyolefin film, a special offset ink for a polyolefin film, which is not blended with mineral oil at the expense of quick-drying property, is actually used.

[0006]

However, since such a special offset ink for polyolefin film has a long drying time and a limited number of printers and ink manufacturers, it is of a general oxidation polymerization type (dry oil type). The advent of polyolefin films that can use offset inks has been desired. That is, a general printing company prints pulp-based paper such as high-quality paper and coated paper, and it is common to perform offset printing using a quick-drying ink that is commercially available. Only when printing film or synthetic paper, it was necessary to switch to a special offset ink for non-absorbent materials and print. Therefore, since it takes a lot of time and labor to switch the ink, general printing companies do not actively try to print polyolefin-based films such as synthetic paper, and this is due to this fact. Was one of the causes that hindered its widespread use in offset printing.

[0007]

[Means for Solving the Problems]

[Summary of the Invention] As a result of intensive studies, the present inventors have found that
If petroleum resin is applied in advance on the surface of the polyolefin film or polyolefin synthetic paper on which offset printing is to be performed, even if offset printing is applied and offset ink is applied to the surface after that, the printed polyolefin The present invention has been completed based on the knowledge that it becomes difficult for unevenness to occur on the surface of a film or synthetic paper and for the entire film to curl. That is, the polyolefin film of the present invention is characterized in that one side or both sides of the polyolefin film is coated with petroleum resin and then uniaxially or biaxially stretched.

[Detailed Description of the Invention] [I] Polyolefin Film Having Excellent Printability (1) Structure The polyolefin film having excellent printability of the present invention has a wall thickness of 20 to 3,000 μm, preferably 60 to 200μ
Since the petroleum resin is applied to one or both sides of the m film (including sheet) and stretched, the stretched polio
Petroleum resin layer laminated on one or both sides of reffin film layer
It has a structured structure. (2) ratio the amount of petroleum resin to be laminated by coating on the surface, the film after stretching, generally 0.1 to 10 g / m ^2, preferably from 1 to 3 g / m ^2.

[II] Polyolefin film with excellent printability
Production of rum (1) Raw material (a) Polyolefin film Raw material of polyolefin film with excellent printability of the present invention
As the polyolefin film used as a material,
Various film forming methods such as polyolefin resin, for example
For example, T-die method, calendar method, cast method, inflation
Formed into a film by various forming methods such as
The film with a wall thickness of 20-700 μm (see
(Including g). Specifically, polyethylene
Resin, polypropylene, ethylene / propylene copolymer
Polyolefin resin such as oil, polybutene resin, etc.
-Vinyl acetate copolymer resin, ethylene-acrylic acid
Small amount of olefin monomer such as stell copolymer resin
By copolymerizing (1.8-15% by weight) other comonomer
The obtained crystalline olefin copolymer etc. are
The polyolefin film obtained by molding by the film molding method.
Film or a small amount of inorganic fine powder mixed with the film.
After the insertion, the uniaxial or biaxial stretching is finally performed by the stretching process described later
The film inside the film obtained by axial stretching is
Opaque or translucent synthetic paper with clovoid (Japanese Patent
Sho 46-40794, Japanese Examined Sho 60-36173, Special
JP-B-62-59668, JP-B-63-64310,
JP-A-3-189141))
You can Among these polyolefin films,
With ethylene, propylene or both as main components
By polymerizing or copolymerizing monomers containing more than wt%
Inorganic fine powder 8 to 8 in the obtained polyolefin resin
65% by weight, preferably 16-55% by weight
Polyolefin film containing inorganic fine powder
Film obtained by uniaxial or biaxial stretching
It has a fine cavity inside and a fine crack on the surface.
Transparent stretched film, so-called synthetic paper
It is suitable in terms of wearability.

(B) Petroleum resin The petroleum resin used as a raw material of the polyolefin film having excellent printability of the present invention and applied to the surface of the polyolefin film is usually a carbon number 5 system or a carbon number 9 system, Alternatively, a petroleum resin having a mixture of 5 carbon atoms / 9 carbon atoms is used. Specifically, JET Vol. 37,
According to No. 2 (1989), pp. 75-79, when petroleum resins are classified from the raw material side, aliphatic petroleum resins (C5 petroleum resins) aromatic petroleum resins (C9 petroleum resins) ) Aliphatic / Aromatic or Aliphatic / Alicyclic Copolymer Petroleum Resin (C5 / C9 Petroleum Resin) Cyclopentadiene Petroleum Resin (DCPD Petroleum Resin) Hydrogenated System Broadly divided into petroleum resins.

The petroleum resin used in the present invention means a hydrocarbon resin, which is derived from coke oven gas, coal tar fraction cracked and deep cracked petroleum feedstock, essentially pure hydrocarbon feedstock or turpentine oil. A hydrocarbon raw material or a hydrocarbon polymer derived from turpentine oil, and typical hydrocarbon resins include, for example, coumarone-indene resin, petroleum resin, styrene resin, cyclopentadiene resin, and terpene resin. .. These resins are from Kirk Osmer "Encyclopedia of
Chemical Technology "Volume 3, Issue 11, 343
P., (1066). The coumarone-indene resin is a hydrocarbon resin, a phenol-modified coumarone-indene resin, or a derivative thereof obtained by polymerizing a resin-forming material present in a distillate of coal tar recovered from a coke oven.

Petroleum resin refers to a hydrocarbon resin obtained by polymerizing a thermally decomposed petroleum raw material using a catalyst. These petroleum resins are generally styrene, methylstyrene, vinyltoluene, indene, butadiene, isoprene, piperylene, It contains a mixture of resin formers such as pentylene. The styrene resin is a low molecular weight homopolymer resin of styrene, and a copolymer resin of styrene and, for example, α-methylstyrene, vinyltoluene, butadiene and the like. The cyclopentadiene resin is a homopolymer resin or a copolymer resin of cyclopentadiene derived from coal tar fraction or separated petroleum gas, and the cyclopentadiene resin is capable of holding a cyclopentadiene-containing raw material at a high temperature for a considerably long time. According to the holding temperature, either a dimer, a trimer or a high polymer can be obtained. Terpene resins are polymers of terpenes that are hydrocarbons of the rational formula C ₁₀ H ₁₆ present in most essential oils and oleoresin of plants and phenol-modified terpene resins, such as α-pinene, β-pinene, Mention may be made of dipentene, limonene, myrcene, bornylene, camphene and similar terpenes.

Of these, hydrogenated petroleum resins having a softening point (ring and ball method) of 70 to 150 ° C. are particularly preferable in the present invention. This hydrogenated petroleum resin is manufactured by Arakawa Chemical Co., Ltd. under the trade name of “ALCON”, Yasuhara Chemical Co., Ltd. under the trade name of “CLEARON”, Tonex Co., Ltd. under the trade name of “ESCOREC”, Mitsui Petrochemical Co., Ltd. The product name "FTR" and the product name "Maruka Kuriya" manufactured by Maruzen Petrochemical Co., Ltd. can be mentioned.

(2) Coating cloth (a) Coating method For coating petroleum resin on the surface of the polyolefin film before stretching, it is dissolved in various solvents such as toluene, xylene and mineral spirit to prepare 10 to 60% by weight. It can be applied as a concentrated solution. When such a diluent is used, it is preferable to dry it in a dryer and then move to the next stretching step. It is also possible to apply the undiluted solution by heating it to the melting point or higher. (b) coating timing As the timing of coating the petroleum resin on the surface of the polyolefin film, when a uniaxially stretched film is obtained, it is applied before the uniaxial stretching, and when a biaxially stretched film is obtained, before the longitudinal stretching. Alternatively, it is preferably applied after the longitudinal stretching and before the lateral stretching. (c) Coating means As a means for coating such a petroleum resin on the surface of the polyolefin film before stretching, specifically, gravure coating, Mayer bar coating, roll coating, blade coating, size press coating Known coating means such as coating and hot melt coating can be adopted. In particular, in the production of a biaxially stretched film, if the coating is performed before stretching, the coating can be performed with an inexpensive and small coater device that does not occupy a space as compared with the case where the coating is performed after stretching. (d) Coating amount The coating amount depends on the draw ratio, but is generally 2 to 20.
It is within the range of g / m ² .

(3) Elongation (a) Elongation The polyolefin film coated with the above petroleum resin is
Further, by stretching at a temperature lower than the melting point of the polyolefin resin, a uniaxially stretched or biaxially stretched polyolefin film or synthetic paper can be obtained. (b) Stretching Conditions Therefore, the heating temperature of the polyolefin resin during stretching is generally 3 to 30 ° C., preferably 5 to 25 ° C. lower than the melting point of the polyolefin resin. The stretching at this time is unidirectional or bidirectional, and therefore the number of stretching axes is uniaxial or biaxial. The stretching ratio is generally 1.3 to 15 times, preferably 3.5 to 10 times. By this drawing step, the organic or inorganic fine powder is 8 to 6
When the polyolefin resin film containing 5% by weight is stretched, fine cracks are formed on the surface and fine voids (voids) are formed inside the film, and the whiteness and opacity of the film, the printing ink The adhesive strength increases. In addition, another resin film is laminated before or after the stretching step, if necessary.

(4) Other additional treatments Further, pigment coating or the like may be performed on the film to further improve the suitability for offset printing. Pigment Coating The pigment coating can be carried out according to a general coating method for coated paper. Examples of the pigment used for pigment coating include clay, talc, calcium carbonate, magnesium carbonate, aluminum hydroxide, silica, aluminum silicate, calcium silicate, plastic pigment, silica-containing composite latex and the like used for ordinary coated paper. be able to. As the adhesive used at this time, latex such as SBR (styrene-butadiene rubber), MBR (methacryl-butadiene rubber), acrylic emulsion, starch, PVA (polyvinyl alcohol), CMC
(Carboxymethyl cellulose), methyl cellulose and the like can be mentioned.

[III] Offset Printing The thus obtained polyolefin film having excellent offset printing properties of the present invention is subjected to offset printing by adhering the offset ink to the surface thereof in an offset printing machine. (1) Offset ink Generally, such an offset ink is shown in Table 1 above.
Further, as shown in Table 2, it is basically composed of a main agent composed of a pigment and a vehicle, and an auxiliary agent composed of a viscosity modifier, a drying modifier and the like. As the pigment,
Azo pigments such as resole red and benzidine yellow,
Lake pigments such as permanent grin, permanent rhodamine, permanent blue, lake red C, brilliant carmine 6B, organic pigments such as phthalocyanine blue, alumina, barium sulfate, red iron oxide,
Inorganic pigments such as yellow lead, navy blue, titanium white, carbon black and the like can be mentioned. Examples of the vehicle include synthetic resin, vegetable oil (drying oil), solvent and the like. Specific examples of these vehicles include linseed oil type such as linseed oil and stand oil, alkyd type such as drying oil-modified alkyd resin, rosin-modified phenolic resin, linseed oil and millet oil mixture, or low-viscosity linseed oil. Dissolves in oil varnish, etc.,
A quick-drying resin type mainly composed of a resin varnish whose viscosity is adjusted by adding a petroleum fraction having a narrow boiling range, a heat-set type such as a varnish obtained by dissolving a resin by adding a petroleum fraction having a narrow boiling range, etc. You can Examples of the viscosity modifier include solvents, diluted varnishes, compounds and the like. Examples of the dryness adjusting agent include a drying agent (dryer) drying inhibitor. Examples of other components include waxes, film enhancers, and anti-backing agents.

(2) Offset printing method In order to perform offset printing on the polyolefin film having excellent offset printability of the present invention using the above-mentioned offset ink, a commercially available offset printing machine is used in the same manner as ordinary offset printing. Can be done. The polyolefin film excellent in printability of the present invention thus obtained is subjected to offset printing, and even if the offset ink is attached to the surface thereof, unevenness occurs on the surface of the printed polyolefin film or the synthetic paper. It is unlikely that the entire film will curl.

[0019]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples below. The parts and% in the examples are on a weight basis unless otherwise specified. In addition, the evaluations in Examples and Comparative Examples were evaluated by the following evaluation methods.

[I] Evaluation method (1) The amount of transfer is measured by using New Best One Process Ink M (manufactured by Toka Dye Co., Ltd.), which is a dry type offset ink commercially available in an offset printing machine, as a curl height evaluation film. Was printed on the entire surface so that the value was 1 g / m ² . And the printed matter is 12c
After being cut into a size of m × 5 cm and left on a flat desk for 1 day, the curl height (h) of the printed matter was measured as shown in FIG. (2) Occurrence of unevenness The transfer amount was 1 g / m ² using New Best One Process Ink M (manufactured by Toka Dye Co., Ltd.), which is a dry offset ink commercially available in an offset printing machine, as an evaluation film, The same ink was partially printed so as to form a one-pine pattern (1 cm x 1 cm). Then, the unevenness of the film formed between the printed portion and the non-printed portion was judged by sensory evaluation. The one with no unevenness was marked with O, the one with severe unevenness was marked with X, and the middle thereof was marked with Δ.

[II] Experimental Example Example 1 Production of Film Melt flow rate (MFR) 0.8 g / 10 min polypropylene (melting point 164 ° C.) 85% by weight, high density polyethylene 5% by weight and average particle size 1.5 μm The composition containing 10% by weight of calcium carbonate was kneaded by an extruder set at 270 ° C., extruded into a sheet, and further cooled by a cooling device to obtain an unstretched sheet. Coating / Stretching Next, petroleum resin (trade name "Alcon" P-128 (softening temperature 125
40% solution of toluene) was applied with a Meyer bar so that the amount of petroleum resin after drying would be 2.5 g / m ² . Then, this sheet was heated again to a temperature of 150 ° C. and then stretched 5 times in the longitudinal direction to obtain a uniaxially stretched film. Printing On this uniaxially stretched film, a dry offset ink commercially available, New Best One Process Ink M (produced by Toka Dye Co., Ltd.), which is commercially available on an offset printing machine, is printed over the entire surface so that the transfer amount is 1 g / m ^2. Was applied. Evaluation The curl height and the occurrence of irregularities of the obtained printing film were evaluated according to the above-described evaluation method. The results are shown in Table 3.
Shown in.

Comparative Example 1 A uniaxially stretched film was obtained in the same manner as in Example 1 except that the petroleum resin was not applied, and offset printing was performed.
The curl height and the occurrence of irregularities of the printed matter were evaluated in the same manner as in Example 1. The results are shown in Table 3.

Example 2 Production of Film 85% by weight of polypropylene (melting point 164 ° C.) having a melt flow rate of 0.8 g / 10 min was mixed with 5% by weight of high density polyethylene and 10% by weight of calcium carbonate having an average particle size of 1.5 μm. The composition was kneaded with an extruder set at 270 ° C., extruded into a sheet, and further cooled by a cooling device to obtain an unstretched sheet. Coating / Stretching Then, the sheet was heated again to a temperature of 150 ° C. and then stretched 5 times in the machine direction. A 40% toluene solution of petroleum resin (trade name "Clearon" P-85 (softening temperature 85 ° C)) manufactured by Yasuhara Chemical Co., Ltd. was applied to the sheet stretched in the longitudinal direction at a petroleum resin amount of 18 g / m ² . Was applied so that Then, it is heated again to a temperature of 160 ° C. and stretched 7.5 times in the transverse direction using a tenter,
Annealing was performed at a temperature of 5 ° C., the temperature was cooled to 60 ° C., and the ears were slit to obtain a biaxially stretched sheet. Printing This biaxially stretched film was coated with a dry offset ink, New Best One Process Ink M (manufactured by Toka Dye Co., Ltd.), which is commercially available in an offset printing machine, over the entire surface so that the transfer amount becomes 1 g / m ^2. Printed. Evaluation The curl height and the occurrence of irregularities of the obtained printing film were evaluated according to the above-described evaluation method. The results are shown in Table 3.
Shown in.

Example 3 Tonex Co., Ltd. was used in place of the petroleum resin (trade name "Clearon") manufactured by Yasuhara Chemical Co., Ltd. used in Example 2.
The same procedure as in Example 2 was carried out except that a petroleum resin (trade name "ESCOLETS" E5320 (softening temperature 125 ° C)) was applied. The results are shown in Table 3.

Comparative Example 2 The same procedure as in Example 2 was carried out without applying the petroleum resin (trade name "Clearon") manufactured by Yasuhara Chemical Co., Ltd. used in Example 2. The results are shown in Table 3.

Example 4 Production of Film (1) 81% by weight of polypropylene (melting point 164 ° C.) having a melt flow rate of 0.8 g / 10 minutes, 3% by weight of high-density polyethylene and 1% calcium carbonate having an average particle size of 1.5 μm.
The composition (A) containing 6% by weight was kneaded by an extruder set at 270 ° C., extruded into a sheet, and further cooled by a cooling device to obtain an unstretched sheet. Then, after heating this sheet again to a temperature of 150 ° C.,
It was stretched twice. (2) Polypropylene with a MFR of 4 g / 10 min (melting point 16
(4 to 167 ° C) 54% by weight and 46% by weight of calcium carbonate having an average particle size of 1.5 µm were mixed and kneaded in another extruder, and then extruded into a sheet form from a die. , Laminate this on both sides of the 5 times stretched film of (1),
A laminated film having a three-layer structure was obtained. Coating / Stretching A 30% toluene solution of hydrogenated petroleum resin (trade name "Alcon" P-125) manufactured by Arakawa Chemical Industry Co., Ltd. was coated on this laminated film so that the amount of hydrogenated petroleum resin was 15 g / m ^2. did. Then heat again to a temperature of about 155 ° C.,
Stretched 7.5 times in the transverse direction using a tenter, annealed at a temperature of 163 ° C, and cooled to a temperature of 60 ° C.
Three-layered structure with ears slit (uniaxial stretching / biaxial stretching /
Uniaxially stretched wall thickness 80 μm (B / A / B = 20 μm / 4
A sheet of 0 μm / 20 μm) was obtained. Evaluation The same printing and evaluation as in Example 1 were carried out. The results are shown in Table 3.

Example 5 Example 4 was repeated except that the petroleum resin manufactured by Arakawa Chemical Industry Co., Ltd. (trade name "ALCON") was replaced with the petroleum resin manufactured by Maruzen Petrochemical Co., Ltd. (trade name "Maruka Kuriya"). The same procedure as in Example 4 was performed.

Comparative Example 3 The procedure of Example 4 was repeated, except that the petroleum resin manufactured by Arakawa Chemical Industry Co., Ltd. (trade name "ALCON") was not applied. The results are shown in Table 3.

Comparative Example 4 A polypropylene-based synthetic paper “Yupo FPG150” manufactured by Oji Yuka Synthetic Paper Co., Ltd. which was not coated with petroleum resin (trade name “ALCON”) manufactured by Arakawa Chemical Industry Co., Ltd. in Example 4
Example 4 except that “(trade name, thickness 150 μm) was used
It carried out similarly to. The results are shown in Table 3.

Comparative Example 5 Production of Film (1) 81% by weight of polypropylene (melting point 164 ° C.) having a melt flow rate of 0.8 g / 10 min, 3% by weight of high-density polyethylene and 1% calcium carbonate having an average particle size of 1.5 μm.
The composition (A) containing 6% by weight was kneaded by an extruder set at 270 ° C., extruded into a sheet, and further cooled by a cooling device to obtain an unstretched sheet. Then, after heating this sheet again to a temperature of 150 ° C.,
It was stretched twice. (2) Polypropylene with a MFR of 4 g / 10 min (melting point 16
4 to 167 ° C.) 51% by weight, hydrogenated petroleum resin manufactured by Arakawa Chemical Industry Co., Ltd. (trade name “ALCON”) 5% by weight, and a composition (B) containing 44% by weight of calcium carbonate having an average particle diameter of 1.5 μm. ) Is kneaded in another extruder, extruded in a sheet form from a die, laminated on both sides of the 5 times stretched film of (1), and then heated again to a temperature of about 155 ° C. And draw 7.5 times in the transverse direction using a tenter,
Anneal at a temperature of 164 ° C, cool to a temperature of 60 ° C, slit the ears, and have a three-layer structure (uniaxial stretching /
Biaxially stretched / uniaxially stretched) wall thickness 80 μm (B / A / B = 2
A sheet of 0 μm / 40 μm / 20 μm) was obtained. Evaluation The same printing and evaluation as in Example 1 were carried out. The results are shown in Table 3.

Comparative Example 6 In Comparative Example 1, the composition B of (2) was added to 50% by weight of polypropylene having a melt flow rate of 4 g / 10 min, 10% by weight of a petroleum resin “Alcon” and calcium carbonate having an average particle size of 1.5 μm. A three-layer synthetic paper was obtained and evaluated in the same manner except that the composition (B) was prepared by mixing 40% by weight. The results are shown in Table 3.

[0032]

[Table 3]

[0033]

EFFECT OF THE INVENTION Since the polyolefin film having excellent printability of the present invention is coated with petroleum resin, it is printed even if offset printing is performed after that and the offset ink is coated on the surface. It is difficult for unevenness to occur on the surface of the polyolefin film or synthetic paper and for the entire film to be curled.

[Brief description of drawings]

FIG. 1 is a perspective view showing a method for measuring a curl height of a printed matter according to an embodiment of the present invention.

[Explanation of symbols]

 1 printed matter 2 flat plate h curl height (cm)

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Claims (1)

[Claims] 1. A stretched polyolefin film produced by uniaxially or biaxially stretching a petroleum resin applied to one or both sides of a polyolefin film.