JPH03189141A - Synthetic paper - Google Patents

Abstract

PURPOSE:To improve the wear resistance and UV ink bonding force by a method wherein on a base layer of a biaxially oriented resin film, a stretched film of paper state styrene graft polypropylene resin film is bonded through a stretched orientation film of crystalline polypropylene resin, and thus a primer layer is provided on a paper state layer. CONSTITUTION:A composition A which is obtained by mixing 12 wt.% of ground calcium carbonate with an average particle diameter of 1.5mum with polypropylene with melt index MI, 0.8 is extruded by an extruder after kneading, and obtained sheet is oriented in the longitudinal direction. Polypropylene B with MI 4 and styrene modified polypropylene C are respectively melt-kneaded by separate extruders and melt-extruded into sheets from dies, and they are laminated on front and rear surfaces of the previously mentioned longitudinally oriented sheet and cooled. The obtained 5 layer sheet is oriented in the lateral direction, and annealing treatment is applied to the sheet in addition, and then, corona discharge treatment is applied to the laminated oriented film, and a primer solution is applied on both surfaces and dried. In this way, a synthetic paper for which primer layers D are provided on both surfaces of a laminated oriented film with 5 layer structure of C/B/A/B/C can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention relates to a synthetic paper with good UV offset printability useful as barcode label printing cards, in-mold label paper, etc.

[Prior art]

Conventionally, bar food labels and inner mold label papers have been coated with valve paper coated with a coating agent made of inorganic filler-containing resin latex and dried. However, labels using this type of paper have poor water resistance, so synthetic paper made of stretched polypropylene film containing inorganic fillers is used for containers with liquid contents such as shampoo motor oil and soft drinks (Japanese Patent Application Laid-Open No. No. 59-7139, No. 59-220358, No. 60
No. -21244, No. 61-259935, Utility Model Kai No. 64
-55970).

These labels are obtained by gravure printing or offset printing on synthetic paper, and have the advantage of excellent water resistance.

Instead of conventional solvent-based inks, UV offset inks are being used as printing inks for in-mold labels and sticker paper, without worrying about volatile solvent pollution and with fast ink drying speeds (Japanese Patent Application Laid-Open No. 1-141736). Publication No.).

6UV disclosed in this Japanese Patent Application Laid-Open No. 1-141736:
Synthetic paper with excellent offset printability is coated on the surface of polypropylene stretched film or polypropylene stretched film containing no al# fine powder with the general formula (wherein A is -N<1
, or represents a polyamine boria 4 mido residue; R1 to R4 are each independently an alkyl group or alkenyl group having 1 to 24 carbon atoms, an aliphatic cyclic hydrocarbon group, or a benzyl group, but at least one One is a group other than H.

In addition, m is θ~300, n, p, and q are each 1~300.
is the numerical value. It is obtained by coating and drying an aqueous solution containing a modified polyethyleneimine represented by the following formula, and has been put to practical use in inner mold labels, stickers, and map paper.

However, even in the use of synthetic paper, magnetic cards such as brivate cards, and IC cards that are repeatedly fed and discharged by rolls into information reading devices, have a slight UV ray when the surface of the card is rubbed by the roll. A few people are concerned that the ink has been observed to fall off the surface of the card, and that the white area where the UV ink has fallen off will become more noticeable after repeated readings, resulting in a poor appearance.

[Problem to be solved by the invention]

An object of the present invention is to provide a synthetic paper with excellent abrasion resistance and excellent UV printing ink adhesion.

[Specific means to solve the problem]

The above purpose is to form a paper-like layer of a styrene-grafted polypropylene resin film through a base layer (B) of a crystalline polypropylene resin having a wall thickness of 3 microns or more in a base layer of a biaxially stretched resin film. This is achieved by using a synthetic paper in which a brimer layer is provided on the paper-like layer of a multilayer film formed by bonding together a stretched film (C).

The present invention will be explained below using the drawings. FIG. 1 is a cross-sectional view of synthetic paper, where A is a support, B is a uniaxially stretched oriented film of crystalline polypropylene as an adhesive layer, C is a uniaxially stretched styrene-grafted polypropylene film as a paper-like layer, and D is a uniaxially stretched oriented film of styrene-grafted polypropylene as a paper-like layer. This is the primer layer.

(Base material layer) As the base material layer, polypropylene, polycarbonate,
Polyethylene terephthalate, polyamide (nylon 6
．． 6, 6.6, 12.6.10, etc.), thermoplastic resins such as polyvinyl chloride, mixtures of these thermoplastic resins, and compositions containing these resins with inorganic fine powder at a ratio of 3 to 45% by weight. A biaxially stretched film or the like is used. Opacity (
JISP-8138) is 80-99%.

This base material layer has high rigidity, and even if the crystals are oriented,
It does not have to be oriented. The crystal orientation has the advantage that the wall thickness can be reduced.

(Adhesive layer) The adhesive layer (B) strengthens the adhesion between the base material layer (A) and the paper-like layer (C), and prevents delamination between the layers when using synthetic paper. ), and although the reason is not clear, it has the effect of improving the adhesive strength of UV printing ink.

The crystalline polypropylene axially stretched film of this adhesive layer needs to be crystal oriented by stretching. or,
A biaxially stretched film is poor in the effect of preventing delamination and the effect of improving the adhesion of UV offset printing ink.

Such crystalline polypropylene has a crystallinity of 40
~70%, 1150-100% propylene homopolymer, fluoropylene number ethylene (0,s~8% by weight) random copolymer, propylene-butene-1 (1-8ut%) random copolymer, propylene-hexene -1(0,5～
6ut%) random copolymer, polypropylene resin such as propylene/4-methylpentene-1 (1 to 8ut%) random copolymer, core resin containing σ, β- of maleic anhydride, acrylic acid, itaconic acid, etc. α0 unsaturated carboxylic acid
A modified polypropylene resin grafted with 1 to 5% by weight can be used. This layer contains 10% by weight of inorganic fine powder.
It may be contained in the following proportions.

l:lJ printing manufacturers apply UV printing to synthetic paper,
The adhesion of the UV ink is evaluated by performing a peel test on the printed surface using an adhesive tape. At this time, if interlayer peeling is observed on the synthetic paper, it is judged to be a defective product.

Therefore, the adhesive layer (B) consists of the surface layer (C) and the base material layer (A).
It also serves to strengthen the adhesive strength of

The thickness of the adhesive layer is required to be 3 microns (μω) or more in order to improve the adhesive strength of the UV offset printing ink and prevent delamination. Further, if this adhesive layer does not substantially contain inorganic fine powder (triple dispersion% or less) and is transparent, the thickness of the adhesive layer should be 1Oμω or less. If it exceeds 10 μω, the gloss of the thin paper-like layer (C) will improve and the paper-like feel will be impaired. From the viewpoint of adhesive strength to prevent delamination, it is preferable that the adhesive layer does not contain inorganic fine powder.

(Paper-like layer) The styrene-grafted polypropylene resin includes 100 parts of polypropylene resin particles and 40 to 40 parts of styrene monomer.
150 direct parts, 0.01 to 1 fij of styrene monomer as a radical polymerization initiator! : Obtained by heating an aqueous suspension containing % of styrene to polymerize styrene monomer.

When producing the above-mentioned styrene-grafted polypropylene resin particles, other vinyl monomers such as methyl methacrylate, acrylonitrile, etc. may be used in combination with the styrene monomer.

Examples of radical initiators include cyclohexanone peroxide, t-butyl peroxybenzoate, methyl ethyl ketone peroxide, dicumyl peroxide, di-
t-butylperoxy)', 2,5-dimethyl-2,
Examples include 5-dibenzoylperoxyhexane, di-t-butyl-di-peroxyphthalate, and the like.

The polymerization temperature is 80 to 1 soc1, preferably 100 to 13
Perform at 0C.

The production of styrene-grafted polypropylene resin particles is disclosed in Japanese Patent Application Laid-open No. 52-50389 and Japanese Patent Publication No. 63-31.
This is described in Japanese Patent No. 503.

The styrene-grafted polypropylene film stretched in the -111i1i1 direction is translucent to opaque, becomes matte by stretching, and has a Peck smoothness of 200 to 1.800.
2 seconds, and the ink adhesion and ink drying properties are good.

The thickness of the paper-like layer is 01 from the viewpoint of adhesion of UV printing ink.
59,797 or more, economically 1 to 5 microns. When the thickness of this paper-like layer is 6 microns or more, (B)
Synthetic paper (with no axially oriented polypropylene resin oriented film and directly integrally adhered to the base material layer (A))
There is no interlayer peeling even when using Example 1 of Japanese Patent Publication No. 63-31503), and the alkyl-modified primer described in Japanese Patent Publication No. 1-141736 is used as an antistatic primer to be applied to this paper-like layer (C). Or cyclopentyl 11
Aqueous solution containing E-polyethyleneimine (primer)
By using UV printing ink, sufficient adhesive strength can be exhibited (Reference Example 1).

In the synthetic paper of the present invention, without being limited to the type of primer, due to the presence of a uniaxially stretched polypropylene resin film, a thin styrene-grafted polybupylene resin uniaxially stretched film paper-like layer with a thickness of 5 to 5 μω is used. U to
By strengthening the adhesion of the V-offset stamp mt+ ink, it is possible to reduce the amount of expensive styrene-grafted polypropylene resin used, which in turn reduces the cost of synthetic paper. It becomes possible to determine the generated paris as a component of the base material layer.

(Manufacture of Laminated Stretched Film) In the manufacture of a laminated stretched film, resin A for forming the base layer (containing inorganic fine powder is preferable in terms of weight reduction).

) is melt-extruded into a sheet through a die of an extruder, and this sheet is stretched 3.5 to 8 times in the longitudinal direction at a temperature lower than the melting point of the resin by utilizing the difference in peripheral speed between the roll groups. Then, using a separate extruder, styrene-grafted polypropylene resin C
At least one side of the sheet (A) is melt-kneaded and fed to a die, laminated in the die, coextruded from the die, and longitudinally stretched in a curved direction (to prevent curling of synthetic paper). The styrene-grafted polypropylene resin C layer is laminated on the outer surface (preferably laminated on both sides), and then tenter-coated at a temperature lower than the melting point of the polypropylene resin of the adhesive layer B and the paper-like layer C. The polypropylene film is stretched 4 to 12 times in the transverse direction using a polypropylene film, then heated and annealed near the melting point of polypropylene tJt>JFI, and then the edges of the resulting laminated stretched film are slit.

The proportion of base material layer A in the thickness of the laminated stretched film is 50
~99%. The thickness of the laminated stretched film varies depending on the application, but for private cards it is 150 to 250 μm,
60 for per food labels and inner mold labels
~110μm, 60 for non-impact printing paper
~70 μ-. The opacity of the laminated stretched film is 85
-98%, whiteness is 88-95%.

(Primer) On the surface of the paper-like layer (C) of the laminated film, polyethyleneimine, a polyethyleneimide adduct of polyamine polyamide, an imine adduct of ethylene/urea, JP-A-1-141
-0M2-0M2-N)i of polyethyleneimine modified product shown by the above formula (1) disclosed in Japanese Patent No. 736
- primers are effective. Among them, Kyusei (1
) is the most effective polyethyleneimine modified product.

Such a modified polyethyleneimine component is a polyethyleneimine adduct of polyethyleneimine or a polyamine polyamide having 1 to 24 carbon atoms/%l:1 alkyl genide, fulkenyl fluoride, cycloalkyl cycloalkyl fluoride, or cycloalkyl genide. It is modified with benzyl halide.

Specific examples of norogenides used as modifiers include methyl chloride, ethyl bromide, n-butyl chloride, lauryl chloride, stearyl iodide, oleyl chloride, cyclohexyl chloride, and benzyl chloride.

The degree of polymerization of polyethyleneimine can be arbitrary as long as the effects of the present invention are achieved, but it is generally 200 to 30.
The one in parentheses is used.

Polyethyleneimide adduct of polyamine polyamide is
A polyamine polyamide obtained by reacting a polyalkylene polyamine such as ethylenediamine, diethylenetriamine, or triethylenetetramine with a dibasic acid such as adipic acid, glutaric acid, or co-phosphoric acid, and further adding ethyleneimine to it. Any molecular weight can be used for the polyamine polyamide, but preferably 500
~20,000. Any polymerization degree of ethyleneimine can be used, but preferably 2.
It is 0-300.

Modification is carried out by adding the above-mentioned halides as modifiers to polyethyleneimine or polyethyleneimine adducts of polyamine polyamides, and adding water and/or hydrophilic solvents (specific examples include ethyl alcohol, isopropyl alcohol, etc.) as necessary. Alcohols, glycols such as ethylene glycol and propylene glycol, and seronlubes such as ethylene glycol monoethyl ether and ethylene glycol monoethyl ether acetate, etc.
The dissolution in water) is carried out by heating at 50 to 200 C, preferably 80 to 120 C, for 5 to 30 hours with stirring in the presence of 1111°C (1/11 JOg water or higher).

This primer aqueous solution may contain other components such as an antistatic agent, a drying accelerator, and the like.

(Antistatic agent) The antistatic agent used as an optional component in the present invention is a water-soluble tertiary to quaternary nitrogen-containing polymer. Here, "quaternary" also includes "both sexes."

Such a nitrogen-containing layer combination can be produced by polymerization of the corresponding nitrogen-containing single fragments and, if necessary, quaternization of the resulting tertiary nitrogen-containing polymer. Specific examples of suitable nitrogen-containing cable mounts include those listed in (i).

(A) (D) R' CHCH2C0 O) (...) Here, in each formula, R5 is hydrogen or a methyl group, R6 and R
7 is each a lower alkyl group (having 1 to 4 carbon atoms, preferably 1 to 2 carbon atoms), R' is a saturated or unsaturated alkyl group or cycloalkyl group having 1 to 22 carbon atoms, and X- is quaternized N+ counteranion (e.g. halide (especially chloride)), M is alkali metal ion (especially sodium, potassium or lithium) % A is carbon number 2-6
represents an alkylene group. Quaternary nitrogen-containing monomer (b),
(d) and (f) are polymerized in the form of their precursors ((a), (c), and (e)), and then quaternized with a cationizing agent such as alkyl halide, dimethyl sulfate, or monochloroacetic acid ester. It goes without saying that it can be made to exist in the polymer by doing so. The salt (MX>) formed by the alkali metal ion (M) and counteranion (X) can be removed by r separation, ion exchange, etc., if necessary.

Although it is necessary that the antistatic agent be water-soluble, it is not desirable that it be excessively water-soluble. Therefore, this tertiary to quaternary nitrogen-containing polymer is preferably a copolymer with a hydrophobic monomer.

Examples of hydrophobic monomers include styrene or its nuclear substituted products or side chain substituted products, esters of acrylic acid or methacrylic acid, vinyl halides, and others.

Particularly suitable antistatic polymers are those obtained by copolymerizing the following components (a) to (C).

(a) Monomers (a) to (f) 20 to 40"%5 (b) CH2-C-COOR' 6 to 80% by weight (
In the formula, R9 represents an alkyl group, an alkylene group, or a cycloalkyl group having 1 to 24 carbon atoms; In the combination, the monomer of component (a) is the monomer (he) of O1I, and X- is C1-.

(Drying Accelerator) When the primer contains an inorganic salt, the drying speed of the offset ink increases. However, since the presence of a water-soluble inorganic salt reduces the water-resistant adhesion of the ink, it is not preferable to have it present in an excessively large amount.

Examples of preferred water-soluble inorganic salts include sodium carbonate, potassium carbonate, sodium bicarbonate, sodium sulfite, and other alkaline salts, as well as sodium chloride, sodium sulfate, sodium nitrate, sodium nitrate, and other neutral salts. .

In addition to such water-soluble inorganic salts, epichlorohydrin adducts of polyamine polyamides, water-soluble organic solvents, surfactants, water-soluble polymers, fine powder substances, and other auxiliary materials can be included.

In particular, if the synthetic paper is used for purposes such as inner mold labels for fancy foods, non-impact printer paper, etc. where the paper is subject to heat, use an epichlorohydrin adduct of polyamine polyamide (Japanese Patent Publication No. 35-3547), which is a crosslinking agent for polyethyleneimine. It is effective to combine them.

The concentration of the aqueous brimer solution is 0.03 to 1% by weight, and the brimer is applied to the paper-like layer of the laminated stretched film using a roll, blade, air knife, etc., and dried to obtain a synthetic paper that is suitable for UV offset printing.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples. In addition, the part in the example is i! It is a standard.

Production Example of Styrene Grafted Polypropylene Example 1: Into an autoclave with content #L3g, add 14001 pure water and 14f polyvinyl alcohol as a suspending agent to make an aqueous medium, and add homopolypropylene particles (Mitsubishi Oil Kasei “Mitsubishi Noblen MA-”
6, trade name, melting point 164r) 490f was suspended by stirring. Separately, t-butyl peroxybenzoate i, ty as a polymerization initiator was dissolved in 51 Oy of styrene (105 parts per 100 parts of polypropylene), and this was added to the suspension system, and the temperature inside the autoclave was adjusted to 9 CI.
The temperature was raised to ' and maintained at this temperature for 3 hours to impregnate styrene containing a polymerization initiator into the polypropylene resin particles.

This aqueous suspension was heated to 105C and maintained at this temperature for 2 hours to effect polymerization, and further heated to 120C and maintained at this temperature for 5 hours to complete polymerization.

After cooling, the contents are taken out and washed with water to obtain 100 styrene-modified (grafted) polypropylene particles with a particle size of 3 to 4 m.
I got g.

Example 2: Styrene-modified polypropylene particles were obtained in the same manner as in Example 1, except that the amount of homopolypropylene used was changed to s s 7f s and the amount of styrene used was changed to 3331.

Production example of modified polyethyleneimine AM-1: In a four-bottle flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet, a 25% aqueous solution of ethyleneimine adduct of polyamine/polyamide (manufactured by BASF) was added. , trade name [Borimin 5Nj)
The denaturation reaction was carried out for 0 hours. The obtained aqueous solution was mixed into AM-1
shall be.

El-1: In a flask similar to that used in AM-1, a 30% by weight aqueous solution of ethyleneimine (manufactured by Nippon Shokubai Chemical Co., Ltd., trade name [P-1000J 100 parts, n-butyl chloride 15
The mixture was stirred under a nitrogen stream, and a modification reaction was carried out at 80C for 25 hours. The obtained aqueous solution is designated as El-1.

In a flask similar to El-2 1-2A, add Ethicine 49F 30% aqueous violet solution (manufactured by Nippon Shokubai Kagaku Kogyo ■, trade name [P-100
0J, 30 parts of lauryl chloride, and 20 parts of ethylene glycol monoethyl ether were added, stirred under a nitrogen stream, and subjected to a modification reaction at 130C for 20 hours. The obtained aqueous solution is designated as El-2.

El-3 El-1 was produced in the same manner as El-1 except that 20 parts of benzyl chloride was used instead of n-butyl chloride. The obtained aqueous solution is designated as El-3.

AM-0: manufactured by BASF [BORIMIN SNJ (precursor of AM-1) h, T-o: manufactured by Nippon Shokubai Kagaku Kogyo@, l'-P-1000J (ET-
Precursor of No. 1 EN: Ethylene, urea antistatic agent B-1 = Manufactured by Mitsubishi Yuka, trade name [Saftomer ST-000J] B-2: Same product [S7 Tomer 5T-1100J] It is a zwitterionic allyl copolymer whose constituent components are nitrogen-containing monomers.

Polyamine polyamide/ebichlorohydrin adduct c-i: “Arafix 1σ0” manufactured by Arayo Kagaku ■
Example 1 (1) A composition (A ) was kneaded with an extruder set to 270Ci, extruded into a sheet, and cooled with a cooling device to obtain a non-stretched sheet.

This sheet was heated to 145C and then stretched 5 times in the machine direction.

(2) Polypropylene with Ml 4 (melting point 1e4C
) (B) and the styrene-modified polypropylene (C) obtained in Example 1 are melt-kneaded at 2600 in separate extruders, fed to a die on the 2nd stand, laminated in the die, and then sheeted from the die. It was melt-extruded into a shape, laminated on the surface knitted surface of the longitudinally stretched sheet of (1) above, and then cooled to 50C.
The five-layer sheet was heated to 155C, stretched 7 times in the transverse direction using a tenter, further heated to 161C for annealing treatment, and then the laminated stretched film was subjected to corona discharge treatment. Next, a 1% aqueous solution of ethyleneimine adduct of inpropyl modified polyamine polyamide (AM-1) was applied to both sides (solid content: o, o sy7m''), and after drying, the ears were slit at 45R. Wind it up, C/B
/A/B/C 5-layer structure (2μ■/3μm140μm3
Primer on both sides of laminated stretched film of μi/2μi)
A synthetic paper provided with layer AM-1 was obtained.

The thickness of this synthetic paper is 150.1 μ■, the opacity is 90%,
Density o, trf//ds Beck smoothness so.

It was seconds.

Example 2 (1) A composition (A) consisting of 79 m of Ml4 polypropylene, 5 parts of high-density polyethylene, and 16 parts of heavy calcium carbonate was melted at 270 C using an extruder, extruded into a sheet, cooled to 55 C, and then heated to 145 t. :', and then stretched 5 times in the longitudinal direction at the same temperature using the difference in circumferential speed between the roll groups.

(2) Composition (B) of 97ml 1% of Mis polypropylene and triple firing layer and styrene-modified polypropylene (C) obtained in @2 were separated using separate extruders.
The mixture was melted and kneaded at 70°C, fed to a die at 60°C, laminated in the die, coextruded through the die into a sheet, laminated on the front and back sides of the longitudinally stretched sheet of (1), cooled to 60°C,
Heated to 8℃, stretched 7 times in the transverse direction using a tenter, and further stretched 1
Annealing treatment was performed by heating to 61°C, corona discharge treatment, brimer (El-1) treatment, and the ears were slit.
A synthetic paper with a thickness of 150.1 .mu.m was obtained by forming a stretched film of 34 .mu.m/4 .mu.W/4 .mu.II) with primer layers on both sides.

The opacity of this synthetic paper is 92%, and the Beck smoothness is 600.
It was seconds.

Reference Example 1 (1) 12 weight 1% of ground calcium carbonate with an average particle size of 1.5 cm was added to polypropylene (melting point 164°C) with an MIo of 8.
The composition mixture (based on the total weight of polypropylene) was kneaded in an extruder set at 270°C, extruded into a sheet, and cooled with a cooling device to obtain a non-stretched sheet.

This sheet was heated to 145°C and then stretched 5 times in the machine direction.

(2) Sudelene-modified polypropylene (C
) was melt-kneaded at 260°C with an extruder, extruded into a sheet from a die, and laminated on the front and back sides of the longitudinally stretched sheet (1).
A synthetic paper having a structure in which primer layers (AM-1) were provided on both sides of a stretched film having a structure (C=lOp■/130μ-/Ioμ■) was obtained.

The opacity of this synthetic paper is 95%, and the Beck smoothness is 400.
The thickness was 150.1 μm.

Comparative Example 1 In Reference Example 1, a synthetic paper having a structure in which the lip gap of the die was changed and a primer layer (AM-1) was provided on the surface was obtained.

The thickness of this synthetic paper is 150.1μ■, and the opacity is 85
%, Beck smoothness was 1400 seconds.

Comparative Example 2 In the same manner as in Example I except that the lip gap of the die was changed, 5 layers (C/B/A/B/C=2μ/L5
A synthetic paper having a structure in which a primer layer was provided on both sides of a stretched film having a structure (μ■/1474/15μ■/2μ■) was obtained.

The thickness of this synthetic paper is 150.1 μ■, and the opacity is 90%.
, Beck smoothness was 600 seconds.

Comparative Example 3 (1) A composition containing 79% by weight of polypropylene with a melt index (MI) of 0.8, 5% by weight of high-density polyethylene, and 16% by weight of heavy calcium carbonate with an average particle size L of 5 μm was prepared. After mixing in an extruder set at 2°C, the mixture was extruded into a sheet and cooled with a cooling device to obtain a non-stretched sheet. This sheet was heated to 140°C and then stretched 5 times in the machine direction.

(2) Polypropylene with an MI of 4.0 (Q and Ml of 4.0
Composition (B) prepared by mixing calcium carbonate with an average particle size of 1.5μ in polypropylene of
The sheets were laminated and coextruded in separate extruders set at
) was laminated on both sides of a 5-fold stretched sheet F, then cooled to 60°C, heated at about 160°C, and horizontally stretched 7 times with a tenter.
．． Stretched 5 times, annealed at 165°C, 5oc
Cool at t and slit the ears to form a 5-layer structure (C/B/A
/B/C=30μm/3μ■A1μ■/3μ-/30μ
(2) A stretched film was obtained.

After corona discharge treatment was applied to both sides of this stretched film, an aqueous solution of Brimer (AM-1) was applied to both sides at a concentration of 0.05 μm (solid content) and dried to give a thickness of 150.1 μ-1 and an opacity of 9.
A synthetic paper with a Bekk smoothness of 300 seconds was obtained.

Comparative Example 4 (1) Mx o, a polypropylene 79 weight 5,
A composition (4) consisting of 5% by weight of high-density polyethylene and 16% by weight of calcium carbonate powder was melt-kneaded using an extruder, then extruded into a V-shaped shape at a temperature of 250°C through a die, and the mixture was extruded at a temperature of about 50°C. The sheet was cooled until then. Next, this sheet was heated to about 140° C. and then stretched 5 times in the longitudinal direction using the difference in circumferential speed between the roll groups to obtain a base material layer.

(2) 55 weight layer of polypropylene with an MI of 4.0 and 45 weight % of ground calcium carbonate with an average particle size of 1.5μ.
The composition (C) mixed with the above was melt-kneaded in another extruder set at 250°C, laminated onto the front and back surfaces of the base layer in a die-like manner, and then cooled to 80°C. Approximately 1
Preheat to 58°C, stretch the laminate 7x in the transverse direction using a tenter at a sheet temperature of about 155°C, pass through an oven at 155°C, then cool to room temperature and corona discharge treatment for 3 layer (C/A/C=5μ■/140μ115μ
A stretched film having the structure N) was obtained.

Brimer (AM-1
) An aqueous solution was applied at a solid content of 0.04 t/nl and dried to obtain synthetic paper having a wall thickness of 150.1 μm, an opacity of 93%, and a Beck smoothness of 300 seconds.

Examples 3 to 9 Synthetic paper having a wall thickness of approximately 150.1 μι was obtained in the same manner as in Example 1, except that the material shown in Table 1 was used as a brimer in a solid amount of 0.061 wt wl (one side). .

Example 10 Synthetic paper with a wall thickness of about 150 μm was produced in the same manner as in Example 1, except that the longitudinal stretching temperature of the composition was changed to 160° C., and the 5-layer sheet was stretched in the transverse direction at 185° C. Obtained.

The opacity of this synthetic paper is 72%, and the Beck smoothness is 330.
seconds, density is 0.98t/A, adhesion of UV printing ink,
The transferability and abrasion resistance were both good.

(Evaluation) Examples 1 to 10, Comparative Examples 1 to 5 Regarding the synthetic paper obtained in Reference Example 1, the ultraviolet curable offset printing ink Toka Shiki Kagaku Kogyo Seisaku Best Cure 161” (product name) Dainippon UV printing was performed using Ink Kogyo Ichi New DC-OL'' (trade name')', and the adhesion, transferability and abrasion resistance were evaluated by the following methods.

The results are shown in Table 1.

[Measurement of ink adhesion]

A polypropylene sheet coated with a coating agent, an uncoated polypropylene v-)K, and an ultraviolet curable ink (manufactured by Toka Shiki Kagaku Kogyo ■, Pestocure-161) were tested using an RI tester (manufactured by Mei Seisakusho) at approximately s f/P. 2511! / 2511! After drying by passing the irradiation for 10 times at a speed of /min, apply Sellotape LP to the surface.
-24 was pasted with Chiban (trade name), rubbed 5 times while pressing lightly with a ball of gauze, and the tape was quickly peeled off to evaluate ink adhesion.

X: Transfer ink 50 to ioo% peeling [Measurement of ink transfer properties] Quist Cure-161 ink (smear) was applied to synthetic paper coated with a coating agent using an RI tester at a normal rate of 1.5 tons//
The printed ink surface was visually observed to evaluate whether there were any transfer defects such as coating streaks or white spots.

FIG. 1 is a cross-sectional view of the synthetic paper of the present invention.

Claims (1)

[Claims] 1) A uniaxially stretched film of a paper-like layer of a styrene-grafted polypropylene resin film is added to the biaxially stretched film base layer (A) via a uniaxially stretched oriented film (B) of a crystalline polypropylene resin having a wall thickness of 3 microns or more. Synthetic paper formed by providing a primer layer on the paper-like layer A of a laminated film formed by bonding (C) together.