JPH0931221A - Surface-treated polypropylene film and metallized polypropylene film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a surface-treated polypropylene film which is excellent in wettability after surface treatment, printability to printing ink, blocking resistance, heat resistance, transparency, metallizing properties and has very small reduction in the wettability with time and a metallized film excellent in metallizing strength. SOLUTION: A polymer composition comprising 97-80wt.% of a crystalline propylene polymer of >=96% isotacticity and 3-20wt.% of a hydrogenated petroleum resin having a softening point of 90-140 deg.C and a bromine value of <=14 is used to produce polypropylene film and the film is subjected to flame treatment on at least one face to give the objective surface-treated polypropylene film.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to the wettability after surface treatment,
A surface treatment that is excellent in printability against printing inks (especially water-based inks), blocking resistance (less blocking between films), heat resistance, transparency, metal vapor deposition, and very little deterioration in wettability over time. The present invention relates to a polypropylene film and a metal vapor deposition film having excellent vapor deposition strength (adhesive force between a metal vapor deposition film and a surface-treated polypropylene film).

[0002]

2. Description of the Related Art Polypropylene films, especially stretched polypropylene films, are widely used as packaging materials because of their excellent mechanical strength, transparency, glossiness and protective properties. Furthermore, when it is subjected to secondary processing such as printing or metal deposition, corona discharge treatment is a typical example in order to improve printability and adhesion to other substances in laminating and coating of adhesion to metal. A method of applying various surface treatments to oxidize the film surface to improve the wettability is used.

[0003]

However, even if the surface of a polypropylene film is subjected to corona discharge treatment, it is difficult to maintain high wettability for a long period of time, and temporarily, high wettability (50 dyne) is maintained. / Cm or more), the surface of the polypropylene film may be roughened, pinholes, strikethrough, etc. may occur, resulting in a significant adverse effect on the film appearance. Furthermore, in response to recent environmental problems, solvent removal and water-based gravure printing inks are rapidly advancing, but since polypropylene film has a poor affinity with water-based gravure printing inks, adhesion between ink and film There is a problem in that the strength is lowered, and the film peels off or comes off due to blocking between the films.

[0004]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned various problems, and more specifically, the wettability after surface treatment, the printability with respect to printing ink (particularly aqueous ink), and the blocking resistance ( The film has less blocking), has excellent heat resistance, transparency, and metal vapor deposition, and has a very low wettability deterioration over time. The metal vapor-deposited film having excellent adhesive strength) is provided.

[0005]

The present invention has the following arrangement. (1) 97-80% by weight of a crystalline propylene polymer [A] having an isotacticity of 96% or more and a softening point of 90-1.
Hydrogenated petroleum resin [B] having a bromine number of 14 or less at 40 ° C is 3 to
A surface-treated polypropylene film [E], characterized in that at least one side of a polypropylene film [D] obtained by using a polymer composition [C] of 20% by weight is subjected to frame treatment.

(2) The wetting index of the film surface of the surface-treated polypropylene film [E] described in the item 1 is 50d.
A surface-treated polypropylene film [F] having a yne / cm or more.

(3) A surface-treated polypropylene film [H] which is a stretched polypropylene film [G] obtained by stretching the polypropylene film [D] described in the above item 1, at least one surface of which is subjected to frame treatment. ].

(4) Metal-deposited on the surface-treated polypropylene film [E] described in the above item 1, the surface-treated polypropylene film [F] described in the above item 2, or the surface-treated polypropylene film [H] described in the above item 3. Vapor-deposited polypropylene film [I].

A detailed description will be given below. The crystalline propylene polymer [A] used in the present invention is a propylene polymer having a crystallinity of isotacticity of 96% or more, preferably 97% or more. The propylene polymer is a homopolymer of propylene. , A copolymer of propylene and one or two kinds of α-olefin (butene-1, 4-methylpentene-1, hexene-1, etc.), and specifically, a crystalline propylene homopolymer, Examples thereof include a crystalline propylene-ethylene copolymer, a crystalline propylene-ethylene-butene-1 copolymer, and a polymer using a homopolymer and / or a copolymer thereof.

A film using a propylene polymer having an II of much less than 96% causes a decrease in heat resistance and causes a problem that the film is thermally shrunk in a secondary processing step such as a printing step or a metal deposition step. It is not preferable because

The method for producing the crystalline propylene polymer [A] is described, for example, in JP-A-58-104907, that is, as an organic aluminum compound, for example, triethylaluminum, diethylaluminum monochloride, or the like, or A solid product obtained by reacting a reaction product of an organoaluminum compound and an electron donor such as diisoamyl ether or ethylene glycol monomethyl ether with titanium tetrachloride is used as an organoaluminum compound such as triethylaluminum or diethylaluminum monomethyl ether. Chlorides and the like and aromatic carboxylic acid esters, for example, benzoic acid alkyl ester, p-
Methyl toluate, p-ethyl toluate or p-
Combined with 2-ethylhexyl toluate, etc., one step of propylene in the presence of a catalyst having a molar ratio (V / III) of the aromatic carboxylic acid ester and the solid product set to 0.1 to 10.0. The method of obtaining by polymerizing above can be illustrated. In this case, one stage means a division of continuous or temporary supply of these monomers.

The degree of isotacticity (hereinafter sometimes abbreviated as II) used in the present invention is the weight percentage of the residue after extraction with boiling n-heptane for 12 hours. The hydrogenated petroleum resin [B] used in the present invention has a softening point (ring and ball method) of 90.
~ 140 ° C, preferably 100-135 ° C, bromine number 14
The following is preferably a hydrogenated petroleum resin of 10 or less. A film using a hydrogenated petroleum resin having a softening point much lower than 90 ° C. has a significantly low blocking resistance, and conversely 14
The transparency of a film using a hydrogenated petroleum resin that greatly exceeds 0 ° C is significantly reduced. Furthermore, hydrogenated petroleum resin having a bromine number of more than 14 and crystalline polypropylene [A]
It has poor compatibility with and reduces the transparency of the obtained film.

The method for producing the hydrogenated petroleum resin [B] is a petroleum unsaturated hydrocarbon, that is, an aromatic hydrocarbon having a double bond in the side chain, a cyclopentadiene hydrocarbon, or a higher olefin hydrocarbon. As a main raw material, sulfuric acid, anhydrous aluminum chloride, boron fluoride, Friedel-Crafts catalyst and the like are polymerized, and hydrogen is added to the unsaturated bond in the polymerization product. Typical commercial products of the hydrogenated petroleum resin [B] used in the present invention are the "Alcon P" series manufactured by Arakawa Chemical Industry Co., Ltd. and the "Marukalets" manufactured by Maruzen Petrochemical Co., Ltd.
Examples include the series and the product name "Escorets" series manufactured by Tonex Co., Ltd.

The polymer composition [C] used in the present invention is a composition comprising 97 to 80% by weight of the crystalline propylene polymer [A] and 3 to 20% by weight of the hydrogenated petroleum resin [B]. . The film using the composition in which the hydrogenated petroleum resin [B] is much less than 3% by weight causes a decrease in the wetting index of the film surface after the frame treatment with the lapse of time, which deteriorates the printability and causes the metal vapor deposition film and the film. The adhesive strength of
A film using a composition in which the hydrogenated petroleum resin [B] greatly exceeds 20% by weight, the heat resistance of the film decreases,
Moreover, the blocking resistance is significantly reduced. That is, the film using the polymer composition [C] containing 3 to 20% by weight of the hydrogenated petroleum resin [B] has a very small wetting with time after flame (flame) treatment, and the printing ink, especially the aqueous solution. It has excellent printability with respect to the ink, excellent blocking resistance, and strong adhesion to the metal vapor deposition film.

Further, in the polymer composition [C], various additives which are usually added to the crystalline olefin polymer such as an antioxidant, a lubricant, an antistatic agent and an antiblocking agent are added to the present invention, if necessary. It can be appropriately blended within a range that does not impair the purpose. The method for producing the polymer composition [C] includes a crystalline propylene polymer [A] and a hydrogenated petroleum resin [B].
Can be used to obtain a composition by uniformly mixing the mixture with a mixer such as a Henschel mixer or a tumbler mixer. If necessary, the obtained polymer composition may be mixed at 180 to 300 ° C. using an extruder. A method of melt-kneading at a temperature to obtain a pellet-shaped polymer composition [C] can also be exemplified.

Examples of the polypropylene film [D] used in the present invention include a non-stretched film, a stretched film (uniaxially stretched and biaxially stretched), and the like. The surface-treated polypropylene film obtained has mechanical strength (rigidity, heat resistance, etc.). ), A stretched film is preferable because it has excellent transparency, gloss, water vapor barrier property, gas barrier property, and rigidity and heat resistance so that wrinkles are not generated during surface treatment and metal deposition and workability is excellent. The thickness of the polypropylene film [D] is preferably 5 to 100 μm, and 10 to 60
μm is more preferred. The polypropylene film [D]
Examples of the manufacturing method of T can include a T-die method, a tubular method that is simultaneous biaxial stretching, a tenter method that is sequential biaxial stretching, and the like, and multistage stretching can also be illustrated as necessary.

The surface-treated polypropylene film [E] of the present invention is obtained by subjecting at least one surface of the polypropylene film [D] to a frame treatment, the affinity with the surface-treated polypropylene film [E] and printing ink, and the surface-treated polypropylene film. [E] and the wettability index of the treated surface is 50 dyne / cm in terms of adhesion strength with the metal vapor deposition film.
The above is preferable, and a film having a rate of 54 dyne / cm or more is more preferable. As the frame processing method, a frame (flame) processing device manufactured by Flinburner, Inc. of the United States,
A frame processing method using a frame (flame) processing device manufactured by esseCI of Italy can be exemplified.

A corona discharge treatment method is widely known as a surface treatment method for a film. The wetting index of the film surface is 50 dyne / cm by the corona discharge treatment method.
It is difficult to achieve the above, and if it is 50 dyne / cm.
Even if the above-mentioned degree of treatment is obtained, there are disadvantages that the surface of the film is roughened, pinholes, strike-through, etc. are caused, the appearance of the film is significantly adversely affected, and blocking between the films becomes remarkable.

The metal-deposited polypropylene film [I] of the present invention is a metal-deposited film obtained by metal-depositing the surface-treated polypropylene film [E], [F] or [H] of the present invention. The thickness of the metal vapor deposition layer is usually in the range of 50 to 800 angstroms, and not only the entire surface (both sides) and one surface but also a partially metal vapor deposited film can be exemplified. The method for producing the metal-deposited polypropylene film [I] is
The degree of vacuum in an apparatus equipped with a roll-out film feeding section, a vapor deposition section, and a winding section is set to 10 ^-4 Torr or less, and a desired metal such as aluminum is heated in a container or on a filament in the apparatus. A generally known vacuum vapor deposition method in which the metal is dissolved and vaporized, and vaporized metal molecules are continuously vapor-deposited and wound on the unwound film surface, or a metal constituting a cathode when discharged in a vacuum is used. Examples thereof include a sputtering vapor deposition method that applies the phenomenon of scattering, and ion plating. Although aluminum is the most common metal to be evaporated, gold, silver, copper, nickel, chromium, germanium, selenium, titanium, tin, zinc and the like can be exemplified.

[0020]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples. In addition, the measuring method of the physical property shown in the following Examples and Comparative Examples and the evaluation criteria are shown below. (1) Wetting tension (unit: dyne / cm) According to JIS K-6768-1977. Film immediately after flame treatment or corona treatment, temperature 25 ° C, humidity 5
The treated surface of the film after aging at 0% RH for 7 days was measured. (2) Transparency (unit:%) Based on ASTM D-1003, haze was measured and used as an index of transparency.

(3) Heat shrinkage (unit:%) Length (L ₀ ) 20 cm from the film in the machine direction (MD),
A test piece having a width of 1 cm was cut out, the test piece was heated in an oven at 140 ° C. for 15 minutes, and then the length (L ₁ ) was measured,
The heat shrinkage ratio (S) in the longitudinal direction was calculated by the following formula and used as an index of heat resistance. S = 100 × (L ₀ −L ₁ ) / L ₀ (4) Blocking degree (unit: N / 4 cm ² ) Film [Aging for 24 hours after surface treatment (40 ° C., 5
0% RH)], a test piece (length 7 cm x width 2 cm) was cut out, and the end portions of the two test pieces were overlapped by 2 cm so that the treated surfaces of the film contact each other, and the overlapped portion (overlap area) A weight of 1 kg is placed on 4 cm ² ) and left (temperature 40 ° C .; humidity 50% RH; 24 h). The maximum force required for shearing and peeling the contact surfaces of the two sample films was measured by a tensile tester.

(5) Ink adhesion strength Sample film [Aged for 24 hours after surface treatment (40
Water-based ink (Aqua Color R63F: manufactured by Toyo Ink Mfg. Co., Ltd.) is applied to the treated surface of the product, and left to dry for 24 hours at room temperature and normal humidity, and then a commercially available cellophane adhesive tape is applied to the coated surface. The area of the ink peeled and adhered to the cellophane adhesive tape after being adhered and peeled at 90 ° was evaluated according to the rank of the ink adhesion strength shown below: ○: Area of ink peeled adhered matter is less than 5% △: Ink 5% or more and less than 20% of the area of exfoliation deposits: 20% or more of the area of exfoliation deposits of ink

(4) Vapor Deposition Strength (Unit: N / 15 mm) A vapor deposition surface of a metal (aluminum) vapor deposition film on one side and a polyester film (# 20) are dry laminated, and the peel strength at the adhesive interface is measured by a tensile tester. It was measured at.

The details of the crystalline propylene polymer and hydrogenated petroleum resin used in Examples and Comparative Examples are described below. PP-1: Melt flow rate (230 ° C., 21.18
N) is 3.7 g / 10 min, isotacticity (I
Crystalline propylene homopolymer having I) of 98.4%. PP-2: Melt flow rate (230 ° C., 21.18
N) is 3.8 g / 10 min, ethylene content is 0.4
A crystalline propylene-ethylene random copolymer having a weight% and an isotacticity (II) of 97.6%. PP-3: Melt flow rate (230 ° C, 21.18
N) is 3.5 g / 10 min, isotacticity (I
Crystalline propylene homopolymer having I) of 94.3%.

HPR-1: Alicyclic saturated hydrocarbon petroleum resin having a softening point of 125 ° C. and a bromine number of 7 (Arcon P-125;
Arakawa Chemical Industry Co., Ltd.). HPR-2: Hydrogenated dicyclopentadiene-based petroleum resin having a softening point of 125 ° C. and a bromine number of 6. (Marukalets H-925
C; Maruzen Petrochemical Co., Ltd.) HPR-3: Alicyclic saturated hydrocarbon petroleum resin having a softening point of 115 ° C. and a bromine number of 7 (Arcon P-115; Arakawa Chemical Industry Co., Ltd.)

HPR-4: alicyclic saturated hydrocarbon petroleum resin having a softening point of 80 ° C. and a bromine value of 7 (Arcon P-80; manufactured by Arakawa Chemical Industry Co., Ltd.) HPR-5: a softening point of 175 ° C. and a bromine value 20 hydrogenated dicyclopentadiene-based petroleum resins. (Marukalets H-97
0: Maruzen Petrochemical Co., Ltd.)

Examples 1-7, Comparative Examples 1-8 The above-mentioned crystalline propylene polymers (PP-1, PP-2,
PP-3) and hydrogenated petroleum resin (HPR-1, HPR-
2, HPR-3, HPR-4, HPR-5) as shown in Table 1 below, and tetrakis- as an antioxidant.
[Methylene-3- (3 ', 5'-di-t-butyl-4'
-Hydroxyphenyl) propionate] methane to 0.
The mixture was blended at a blending ratio of 4%, uniformly mixed by a Henschel mixer, and the obtained mixture was charged into an extruder and melt-kneaded to obtain a pelletized composition. Next, the obtained composition was fed into an extruder having a diameter of 65 mmφ, melted at 240 ° C., extruded from a T die, and cooled by a cooling roll at 40 ° C. to obtain a sheet having a thickness of 1 mm.

Next, the obtained sheet was first preheated at 158 ° C. for 120 seconds using a pantograph type biaxial stretching tester, and then 5.0 times in the machine direction at a stretching speed of 10 m / min.
The film was sequentially stretched in the transverse direction by 8.0 times to obtain a biaxially stretched film having a thickness of 25 μm. Further, one side of each of the biaxially stretched films was subjected to flame (flame) treatment or corona discharge treatment. Each predetermined test piece was prepared using the obtained film, and using the predetermined test piece, haze, heat shrinkage, wetting tension,
The blocking degree and the ink adhesion strength were measured. The characteristics are shown in Table 1. Each of the surface-treated biaxially stretched films was attached to a continuous polyester film (# 20) so that the flame (flame) -treated surface and the corona discharge-treated surface were outer surfaces, and the film was continuously set in a vacuum deposition apparatus. The aluminum film is vapor-deposited on the frame (flame) treated surface and the corona discharge treated surface under a vacuum of 5 × 10 ^-5 Torr while being rolled out, and the vapor-deposited film has a thickness of 400 angstrom (± 20 angstrom). A metal-deposited film in which was vapor-deposited with aluminum was obtained. The vapor deposition strength was measured using each of the metal vapor deposition films. The characteristics are shown in Table 1.

Examples 1, 2, 3, 4, 5, 6 and 7 are
While haze, heat shrinkage, wetting tension, blocking resistance (small blocking degree), ink adhesion and vapor deposition strength are simultaneously excellent, Comparative Example 1 uses a crystalline propylene homopolymer having II of 94.3%. Since it is used, the heat shrinkage is not excellent. Since Comparative Example 2 uses a hydrogenated petroleum resin having a softening point of 80 ° C., it has a large degree of blocking and is poor in blocking resistance and ink adhesion strength. Comparative Example 3
Uses a hydrogenated petroleum resin having a bromine number of 20, and has poor haze and ink adhesion strength. Since Comparative Example 4 uses a composition containing 2% by weight of hydrogenated petroleum resin, ink adhesion and vapor deposition strength are not excellent, and Comparative Example 5 uses a composition containing 25% by weight of hydrogenated petroleum resin. Therefore, the heat shrinkage rate is not excellent. Since Comparative Examples 6, 7 and 8 are films using corona discharge treatment as the surface treatment method,
Wetting tension is not excellent.

[0030]

[Table 1]

[0031]

EFFECTS OF THE INVENTION The surface-treated polypropylene film of the present invention has wettability after surface treatment, printability with respect to printing ink (particularly aqueous ink), blocking resistance (less blocking between films), heat resistance, It is suitable for printing films and metal vapor deposition films because it has excellent transparency and metal vapor deposition properties, and has a property that the wettability is extremely small with time. Furthermore, since the metal vapor-deposited polypropylene film of the present invention has a characteristic that it has excellent vapor deposition strength (adhesion between the metal vapor-deposited film and the surface-treated polypropylene film), peeling and cracking of the metal film does not occur. Is suitable for use.

Claims (4)

[Claims] 1. A crystalline propylene polymer [A] having an isotacticity of 96% or more and 97 to 80% by weight and a softening point of 9.
Hydrogenated petroleum resin having a bromine number of 14 or less at 0 to 140 ° C [B]
A polypropylene film [D] obtained by using a polymer composition [C] containing 3 to 20% by weight of the polymer composition [C], at least one surface of which is subjected to a flame (flame) treatment. ]. 2. The surface treated polypropylene film [E] according to claim 1 has a wettability index of 50 dyne on the film surface.
/ Cm or more, the surface-treated polypropylene film [F] according to claim 1. 3. A surface-treated polypropylene film [H], which is a stretched polypropylene film [G] obtained by stretching the polypropylene film [D] according to claim 1, and at least one surface of which is subjected to frame treatment. . 4. The surface-treated polypropylene film [E] according to claim 1, the surface-treated polypropylene film [F] according to claim 2, or the surface-treated polypropylene film [H] according to claim 3 obtained by metal vapor deposition. Metal-deposited polypropylene film [I].