JP2005263896A - Polyproylene film for label and metallized polypropylene film for label and metallized label made of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene film for a label, which is excellent in adhesion to a metallized layer and is excellent in glossiness and processability, and the label made of the same. <P>SOLUTION: The polypropylene film for the label has oxygen atoms bound to carbon atoms at the film surface, wherein ratios (O/C) of oxygen atoms to carbon atoms are 0.2-0.4 and 0.2-0.3 at surface A and surface B, respectively, Ra(A) is 0.012-0.03 μm, Ra(B) is 0.02-0.05 μm and Rt(B)/Ra(B) is 10-30. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polypropylene for label that is used by adhering to PET bottles, PP bottles, food cans and the like via an adhesive, and particularly preferably, when metal vapor deposition is performed, adhesion to vapor deposited metal. The present invention relates to a polypropylene film for labels which is excellent in brightness and gloss and a label comprising the same.

  When a biaxially oriented polypropylene film is used for a metal vapor deposition label, metal vapor deposition is performed on at least one surface, and a printing layer is provided directly on the other surface or a printing layer is provided via an anchor coat layer. Any surface needs to be subjected to surface treatment such as corona discharge treatment in order to ensure vapor deposition or adhesion to the printed layer. In the case of a film subjected to double-sided treatment in this way, there are cases where blocking occurs when the film is wound up in a roll shape or when it is wound up after metal deposition with a vapor deposition machine.

  For this reason, attempts to reduce blocking by specifying the surface roughness and the structure of polar groups introduced on the surface (see, for example, Patent Documents 1 and 2), and slipping by adding organic or inorganic slip agents Attempts to prevent blocking by imparting properties (for example, see Patent Documents 3, 4, and 5) have been proposed.

Such an additive is certainly effective, but adding an organic or inorganic slipping agent to the vapor deposition surface side will cause problems such as loss of glossiness or reduced adhesion of vapor deposition. In applications such as labels that place importance on the degree, practical problems arise.
Japanese Patent No. 1940721 (Claim 1) Japanese Patent No. 2061031 (Claim 1) Japanese Patent No. 3218940 (paragraphs [0002] to [0008]) Japanese Patent No. 3267688 (paragraphs [0002] to [0006], [0009]) Japanese Patent No. 3454421 (paragraphs [0002] to [0005], [0010] to [0012])

  It is an object of the present invention to provide a polypropylene film for a label which is excellent in adhesion and gloss of metal deposition by optimizing the surface of the polypropylene film, and has a greatly reduced blocking when rolled up or deposited. It is what.

In order to solve this problem, the present invention has the following configuration. That is,
(1) The film surface has oxygen atoms bonded to carbon atoms, and the ratio of the number of oxygen atoms to the number of carbon atoms is 0.2 to 0.4 on one surface (surface A), and the other surface (surface B) 0.2 to 0.3 label polypropylene film, the average surface roughness of surface A (Ra (A)) is 0.012 to 0.03 μm, the average surface roughness of surface B (Ra (B)) is 0.02 to 0.05 μm, and the ratio (Rt (B) / Ra (B)) between the maximum surface roughness (Rt (B)) and Ra (B) of the surface B is A polypropylene film for labels, which is 10 to 30.

  (2) The polypropylene film for label is composed of at least three layers in the order of A layer / C layer / B layer, and the resin composition constituting the A layer forming the surface A is an ethylene component and / or a 1-butene component. Is a polypropylene resin composition containing 0.5 to 4 wt% of inorganic particles and / or organic particles of 1000 to 2000 ppm, and the resin composition constituting the B layer forming the surface B is inorganic particles and / or organic It is a resin composition containing 1500 to 3000 ppm of particles, and the cold xylene soluble content of the resin composition constituting the C layer is 0.1 to 3% by weight, as described in (1) Polypropylene film for labels.

  (3) A metal-deposited polypropylene film for a label comprising a metal-deposited layer on the surface A of the label-use polypropylene film according to (1) or (2), wherein the thickness of the metal-deposited layer is 20 to 100 nm, A metal-deposited polypropylene film for labels, wherein the gloss of the surface of the metal-deposited layer is 600 to 900%.

(4) Metal vapor deposition having a UV ink layer on the surface B of the metal vapor-deposited polypropylene film for labels according to (3) via an anchor coat layer, and an adhesive layer provided on the surface of the metal vapor-deposited layer label.
Consists of.

  The polypropylene film for a label of the present invention and the metal vapor-deposited film and metal vapor-deposited label for the label are excellent in adhesion between the polypropylene film and the metal vapor-deposited layer, have excellent durability, and have problems such as blocking through film roll and vapor deposition. Excellent processing suitability due to absence. Moreover, since the glossiness of a vapor deposition surface is excellent, it is suitable for metal vapor deposition labels.

  In the polypropylene film for labels of the present invention, the surface A and the surface B have oxygen atoms bonded to carbon atoms, but the surface A is a surface on which a metal vapor deposition layer is provided, and has adhesion with the vapor deposition metal. In order to ensure, the ratio of oxygen atoms to carbon atoms on the surface A (hereinafter referred to as O / C) needs to be 0.2 to 0.4, more preferably 0.22 to 0.4. 35. If the O / C is too small, the adhesion to the deposited metal is not sufficient, and if the O / C is too large, the surface is deteriorated in the process of introducing oxygen, resulting in a decrease in gloss or a decrease in the adhesive strength. Here, the oxygen introduced into the surface A is usually

Although it is combined with carbon in a chemical state such as, a method of introducing such oxygen includes corona discharge treatment, plasma treatment, flame treatment and the like. In the present invention, a particularly preferred method is corona discharge treatment. In this case, it is necessary to introduce oxygen that becomes the above-mentioned O / C into at least the surface on which the metal vapor deposition layer is provided. However, in order to prevent the deterioration of the resin, the treatment may be performed in an inert gas atmosphere. Preferably, the treatment is performed by replacing air with a gas such as nitrogen gas or carbon dioxide gas. In particular, if the oxygen concentration in the atmosphere exceeds 5%, deterioration of the resin due to oxidation is promoted, so it is preferable to suppress it to 5% or less. Moreover, as a preferable composition of the atmospheric gas, a composition in which nitrogen gas is 80 to 97% and carbon dioxide gas is 3 to 20% is preferable because adhesion to the deposited metal is improved. When such treatment is performed, nitrogen is introduced into the surface in a state where nitrogen is bonded to carbon in addition to oxygen, and the ratio of nitrogen atom to carbon atom (N / C) is preferably 0.01 to 0.00. It is 08, More preferably, it is 0.02-0.06. By setting N / C within this range, the adhesion to the deposited metal is improved. Here, as the chemical state of nitrogen bonded to carbon,

Etc. are exemplified.

  On the other hand, since the surface B is coated with an anchor coating agent, an adhesive, ink, or the like, the O / C of the surface B needs to be 0.2 to 0.3, and more preferably 0.22 to 0.3. The range is 28. If the O / C is too small, there will be a problem with the adhesion to the anchor coating agent, adhesive, ink, etc. If the O / C is too large, the blocking shear force when the film is wound into a roll will be high, and When the film is unwound, wrinkles may occur or the film may be cleaved.

  Next, the average surface roughness (Ra (A)) of the surface A of the polypropylene film for labels of the present invention needs to be 0.012 to 0.03 μm, more preferably 0.015 to 0.024 μm. is there. When Ra (A) is too small, the slipperiness at the time of processing is impaired, which causes surface scratches. On the other hand, if Ra (A) is too large, the surface gloss when the metal vapor deposition layer is provided is inferior, causing a problem in terms of quality.

  On the other hand, Ra (B) on the surface B of the film of the present invention is required to be 0.02 to 0.05 μm, and more preferably 0.025 to 0.04 μm. If Ra (B) is too small, there will be a problem in workability, and if Ra (B) is too large, the unevenness formed on the surface will affect the printed layer, causing a problem in color, or the glossiness of the deposited metal layer Cause lost problems. Further, the ratio (Rt (B) / Ra (B)) between the maximum surface roughness (Rt (B)) and Ra (B) of the surface B needs to be 10 to 30, preferably 15 to 25. When Rt (B) / Ra (B) is too small, the blocking force between the surface of the metal vapor deposition layer and the surface B when the film is wound after providing the metal vapor deposition layer becomes strong, and the film is wound into a roll shape. There is a problem that the metal deposition layer peels off when unwinding later. On the other hand, if Rt (B) / Ra (B) is too large, problems such as white turbidity due to film scraping during processing and a decrease in glossiness of the deposited metal layer occur.

  In order to form such a surface shape, inorganic particles and / or organic particles are added in advance to a polypropylene resin, and after forming into a sheet shape, surface protrusions based on the particles are formed in the stretching step. It is preferable because of excellent controllability of the surface form. In the present invention, it is necessary to form different surface morphologies on the surface A and the surface B, respectively, and it is preferably composed of at least two layers having different additive particle formulations. It is preferable to consist of at least two layers of the B layer forming

  Here, the resin composition constituting the layer A forming the surface A contains an ethylene component and / or a 1-butene component in an amount of 0.5 to 4% by weight, and further 1.0 to 3% by weight. A composition is preferred. By containing a small amount of ethylene component and / or 1-butene component, the formation of spherulites and the like is suppressed, and the surface A undulation is small and the glossiness when a metal vapor deposition layer is provided can be increased. Moreover, in order to obtain said Ra (A), it is preferable to contain 1000-2000 ppm of inorganic particles and / or organic particles in the resin composition which comprises this A layer, More preferably, it is 1300-1800 ppm.

  Here, the inorganic particles are exemplified by inorganic particles selected from natural or synthesized metal oxides such as silica, alumina, talc, calcium carbonate, zeolite, and / or carbonates. Examples of the organic particles include particles made of an insolubilized polymer compound such as a crosslinked polystyrene resin, a crosslinked polymethyl methacrylate resin, and a silicone resin. Among these, the inorganic particles and / or organic particles added to the resin composition constituting the A layer are at least one kind of particles selected from synthetic silica-based particles, synthetic zeolite-based particles, and crosslinked polymethyl methacrylate particles. The average particle diameter of the particles is preferably 0.5 to 5 μm, more preferably 1 to 3 μm.

  On the other hand, it is preferable that the above-described inorganic particles and / or organic particles are also added to the resin composition constituting the B layer forming the surface B, and the concentration of the particles is preferably 1500 to 3000 ppm. More preferably, it is 1800-2700 ppm. For the resin composition constituting the B layer, in order to obtain a desired Rt (B) / Ra (B), it is preferable to use particles having at least two kinds of diameters, and a diameter of 0.5 to 2 μm as the small diameter particles. As described above, it is preferable that the large-diameter particles are 1.3 to 2.5 times the size of the small-diameter particles, and the concentration ratio of the small-diameter particles to the large-diameter particles is in the range of 9: 1 to 6: 4.

Next, as a more preferable form of the film of the present invention, the A layer and the B layer are skin layers, respectively, and a film comprising at least three layers laminated in the order of at least A layer / C layer / B layer having a C layer as a core layer. It is preferable to have it. By doing so, the layer C contains a low concentration of inorganic particles and / or organic particles, and as a result, it is possible to select a resin having a low haze, and when used as a label, it is very excellent in transparency and looks good. It is possible to finish it as a label. Here, the resin composition used as the C layer preferably has a cold xylene soluble content of 0.1 to 3% by weight. When there is too little cold xylene soluble part, it may be inferior to stretchability and may become a film with a high haze as a result. On the other hand, if the amount is too large, the heat shrinkage property and heat resistance are poor, and the flatness deteriorates during processing, causing problems such as label curling. The above-structured polypropylene film for labels is excellent in transparency and adhesiveness, and used as a transparent label. Of course, a particularly preferable configuration is to provide a metal vapor deposition layer on the surface A and use it as a metal vapor deposition label. In this case, examples of the vapor deposition metal include aluminum, zinc, and alloys thereof, but aluminum is preferable because it is excellent in workability and quality, and the thickness of the metal vapor deposition layer is preferably 20 to 100 nm. If the thickness of the metal vapor deposition layer is too thin, a sufficient metallic luster cannot be obtained, causing problems in terms of quality. On the other hand, if the thickness of the metal deposition layer is too thick, the film may lose heat, the internal strain of the metal deposition layer may increase, cracks may occur, and the adhesion between the metal deposition layer and the film may be reduced. Moreover, it is preferable that the surface gloss of the metal vapor deposition polypropylene film for labels obtained in this way is 600 to 900%, More preferably, it is 650 to 850%.

  The metal-deposited polypropylene film for labels of the present invention is provided with an anchor coat layer on the surface B using an anchor treatment agent such as urethane resin, epoxy resin, polyester resin, acrylic resin, polyethyleneimine, etc., for improving adhesion. It is preferable. Although the thickness of this anchor coat layer is not specifically limited, 0.1-1.0 micrometer is preferable.

  Furthermore, it has a UV ink layer through an anchor coat layer, and is formed as a metal vapor deposition label formed by applying an adhesive layer on the surface of the metal vapor deposition layer of the metal vapor deposition polypropylene film.

  This UV ink contains a pigment, an oligomer, a monomer, a photopolymerization initiator, and an additive. The oligomer can be selected from, for example, polyester acrylate, epoxy acrylate, urethane acrylate, polyol acrylate, etc. Can be selected from, for example, 2-hydroxymethyl methacrylate, 1,6-hexanediol acrylate, trimethylolpropane triacrylate, and the like. Examples of the photopolymerization initiator include 2-hydroxy-2-methylpropiophenone, 2, It can be selected from 2-dimethoxy-2-phenylacetophenone and the like, and as additives, a photopolymerization accelerator, a stabilizer, an adhesion-imparting agent, a misting prevention agent, and a wax are blended as necessary. The UV ink is ultraviolet UV ink layer is formed by more hardened.

  The polypropylene resin composition used in the present invention may contain a stabilizer such as an antioxidant, a chlorine scavenger, an antistatic agent, a slipping agent and the like as long as it does not contradict this purpose. Examples of the stabilizer include hindered phenols, hindered amines, phosphites, tocopherols, and lactones. Furthermore, examples of the chlorine scavenger include calcium stearate and hydrotalcite. Antistatic agents include alkylmethyl dibetaine, alkylamine diethanol and / or alkylamine ethanol ester and / or alkylamine diethanol diester, and slip agents include aliphatic amides such as stearic acid amide and erucic acid amide, lauric acid Examples include diethanolamide, alkyldiethanolamine, aliphatic monoglyceride, and aliphatic diglyceride.

  Hereinafter, although the manufacturing method for obtaining the desirable film structure of the polypropylene film for this invention label is demonstrated, of course, it is not limited to the said manufacturing method.

  Extruder I, II, III Extruder equipment comprising three extruders and a joining device for forming a resin sheet of three layers by joining the resin composition extruded from each extruder Resin composition A constituting layer A from I, resin composition C constituting layer C from extruder II, and melt composition extruding resin composition B constituting layer B from extruder III, respectively, and resin composition A layer The molten sheet consisting of / C layer / B layer is extruded from the die, cooled while being pressed with air pressure on a cooling drum of 15 to 60 ° C., and further led to a water bath of 15 to 70 ° C. to be sufficiently cooled and solidified. obtain. Subsequently, the sheet is heated to 125 to 145 ° C. while being in contact with a metal roll, and then stretched in the longitudinal direction 3 to 7 times between rolls having a difference in peripheral speed to obtain a uniaxially oriented film. Next, the uniaxially oriented film is grasped with a clip and introduced into a hot air oven, preheated to 145 to 165 ° C., stretched 6 to 10 times in the width direction, and then allowed to relax 2 to 20% in the width direction. Heat setting is performed at 150 to 170 ° C. In this way, a biaxially oriented film stretched in the longitudinal direction and the width direction is obtained, and after trimming the clip edge gripped by the clip, both surfaces of the biaxially oriented film are subjected to surface treatments such as corona discharge treatment, flame treatment, and plasma treatment. It is wound up after applying. As a preferable means for the surface treatment, a corona discharge treatment is performed after the atmosphere air is replaced with a mixed gas of nitrogen gas and carbon dioxide gas as described above, and at least the surface treatment of the surface A is performed by using nitrogen gas and carbon dioxide gas. It is preferable to use a method of performing corona discharge treatment after substituting the atmospheric air with a mixed gas.

  A metal vapor deposition layer such as aluminum or zinc is provided on the surface A of the polypropylene film for labels thus obtained by the method described above. The metal vapor-deposited polypropylene film for labels can be obtained with an excellent surface gloss of 600 to 900% by setting the thickness of the metal vapor-deposited layer to 20 to 100 nm.

  Next, an anchor coat layer is provided on the surface B of the metal-deposited polypropylene film for labeling, and then printing is performed using UV ink to obtain a printing film. In this case, it is advantageous in terms of cost to use a multi-stage coater capable of consistently applying the anchor coating agent and the UV ink.

  Next, an adhesive layer for adhering to an adherend such as a bottle is provided on the surface of the metal vapor deposition layer of the printed film, and further wound up in a roll while attaching a separator for releasing the adhesive layer. Get a label.

  The measurement methods and evaluation methods used in the examples of the present invention are as follows.

(1) The ratio of the number of oxygen atoms to the number of carbon atoms on the film surface (O / C) and the ratio of the number of nitrogen atoms (N / C)
Using an ESCA spectrometer ES200 type manufactured by Kokusai Electric Inc., the film surface was measured under the following conditions. Excitation X-ray: Al Kα ray (1486.6 eV), X-ray output: 10 kV, 20 mA, temperature: 20 ° C., kinetic energy correction: the kinetic energy value of neutral carbon (—CH 2 —) was adjusted to 1202.0 eV. From the obtained energy value, the ratio of the area of the C1s peak to the O1s peak was O / C, and the ratio of the area of the C1s peak to the N1s peak was N / C.

(2) Melting point Obtained when a 5 mg sample is heated at a rate of 10 ° C./min under a nitrogen atmosphere using a scanning differential calorimeter (DSC) (DSK-1B, manufactured by PERKIN-ELMER). It is defined by the peak temperature (° C) of the endothermic curve accompanying the melting of the crystal. For the sample, each layer is shaved and 5 mg is sampled.

(3) Intrinsic viscosity [η]
According to ASTM D 1601, 0.1 g of a sample is completely dissolved in 100 ml of tetralin at 135 ° C., this solution is measured in a thermostatic bath at 135 ° C. with a viscometer, and the intrinsic viscosity is obtained from the specific viscosity S according to the following formula. The unit is dl / g.

[Η] = S / 0.1 × (1 + 0.22 × S)
(4) Wetting tension It measures based on the measuring method prescribed | regulated to JISK676 by the liquid mixture of formamide and ethylene glycol monoethyl ether. The unit is represented by mN / m.

(5) Heat shrinkage rate Measured according to JIS K1712.

(6) Film thickness It measured using the dial gauge type thickness meter (JIS-B-7509, measuring element 5 mm diameter flat type).

(7) Thickness configuration of film and thickness of metal vapor deposition layer The cross section of the film is photographed with a transmission electron microscope (TEM) under the following conditions, and the thickness configuration of the film and the thickness of the inorganic thin film layer are measured. Apparatus: JEM-1200EX observation magnification made by JEOL Ltd .: 1000 times in the case of a film thickness configuration, 400,000 times in the case of a metal vapor deposition layer thickness, accelerated electrons: 100 kV.

(8) Average surface roughness (Ra), maximum surface roughness (Rt)
According to JIS B0601-1976. The cut-off is 0.25 mm.

(9) Surface gloss Measured according to JISK7105. Digital gloss meter UGV made by Suga Test Instruments Co., Ltd.
Measurement is performed under the conditions of an incident angle of 60 ° and a light receiving angle of 60 ° using −5D.

(10) Blocking resistance A sample of width 3 cm × length 10 cm was overlapped over 4 cm × 3 cm, left in an atmosphere of 40 ° C. and 85% RH for 24 hours under a load of 500 g, and then sheared with a tensile tester. The force (g / 12 cm ² ) required for peeling was measured. Note that this measurement was performed with the surface A and the surface B in contact with each other.

(11) Metal deposition adhesion index (adhesive strength)
Metal was deposited on both sides of the film with a double-sided vapor deposition machine to a thickness of 30 nm and peeled off with cellophane adhesive tape ("Cello Tape" (registered trademark)) manufactured by Nichiban Co., Ltd., and the area where the metal remained attached to the film was processed. The remaining area adhesion index was determined on the basis of 75% or more: 4, 50% or more and less than 75%: 3, 25% or more and less than 50%: 2, or less than 25%: 1. The higher the adhesion index, the better the adhesion.

(12) Uniformity of metal vapor deposition film thickness The lower fluorescent lamp of the metal vapor deposition film is turned on and visually observed from above the metal vapor deposition film. Perform a 20 m inspection in the length direction with a width of 1 m. ○: There is no unevenness in the metal deposition film thickness.

  X: There is unevenness in the metal deposition film thickness, and a dark and dark part is produced by fluoroscopic observation.

(13) Workability at the time of metal vapor deposition As for the workability at the time of metal vapor deposition (whether or not wrinkles are generated, etc.), those having no wrinkles and excellent workability are good, and those having poor workability but no practical problems are Δ Those having poor processability were evaluated as x.

(14) Vapor deposition metal blocking property (vapor deposition metal peeling)
Metal deposition is performed on both sides of the film with a double-sided vapor deposition machine, and the wound product is left in an atmosphere at a temperature of 25 ° C. and a relative humidity of 65% RH, and is wound up at a speed of 200 m / min every day. The peeling was evaluated in terms of the number of days that reached 30 mm in the width direction from both ends of the film. The longer the number of days, the better the resistance to vapor deposition metal blocking.

(15) Cold xylene soluble sample 10 g of sample dissolved in 1000 ml of boiling xylene, slowly cooled to 50 ° C., then immersed in ice water, cooled to 20 ° C. with stirring, allowed to stand at 20 ° C. overnight, and then precipitated. The polymer was separated by filtration, xylene was evaporated from the filtrate, dried under reduced pressure at 60 ° C., and the polymer soluble in xylene at 20 ° C. was recovered, and the weight thereof was measured.

(16) Ethylene content According to the method described in the paragraph “(i) Random copolymer” on page 256 of the Polymer Analysis Handbook (published by Asakura Shoten in 1985), the content was determined by IR spectroscopy.

(17) 1-butene content The 1-butene content is determined from the characteristic absorption at 770 cm ⁻¹ by the IR spectrum measurement method described on page 619 of the Polymer Handbook (published by Kinokuniya, 1995). It was.

(Example 1)
Three extruders, ie, extruders I, II and III, were prepared. As a resin composition constituting the layer A from the extruder I, a crosslinked polymethyl compound containing 2% by weight of an ethylene component and having an average particle diameter of 1.8 μm. A polypropylene resin composition containing 1500 ppm of methacrylate particles is melt-extruded at 250 ° C., and the resin composition constituting the B layer from Extruder II contains 1% by weight of an ethylene component and has a particle size of 1.8 μm. A polypropylene resin composition containing 2500 ppm of methyl methacrylate particles is melt-extruded at 250 ° C., and a polypropylene resin composition having a cold xylene solubles content of 1.5% by weight as a resin composition constituting the C layer from the extruder III. Were extruded at 250 ° C., respectively, led to a three-layer composite die, and extruded from the die as a three-layer laminated sheet comprising a resin composition A layer / C layer / B layer. Chi, cooled with pressing pneumatically on a cooling drum of 40 ° C., and sufficiently cooled and solidified led further to 50 ° C. water bath, to obtain a cooling sheet. Subsequently, the cooling sheet is heated to 140 ° C. while being in contact with a metal roll, and then stretched 4.8 times in the longitudinal direction between rolls having a difference in peripheral speed to obtain a uniaxially oriented film. Next, the uniaxially oriented film is gripped with a clip and introduced into a hot air oven, preheated to 160 ° C., stretched 9 times in the width direction, and then heat fixed at 160 ° C. while allowing 5% relaxation in the width direction. The surface A of the obtained biaxially oriented polypropylene film was subjected to a corona discharge of 23 W / m ² / min at a film temperature of 60 ° C. in a mixed gas atmosphere of nitrogen and carbon dioxide (carbon dioxide volume ratio 10%). Then, the surface B of the biaxially oriented polypropylene film is subjected to a corona discharge treatment of 23 W / m ² / min at a film temperature of 60 ° C. in a mixed gas atmosphere of nitrogen and carbon dioxide (carbon dioxide volume ratio 10%). And then wound up. The obtained biaxially oriented polypropylene film had an A layer thickness of 1 μm, a B layer thickness of 1 μm, and a total thickness of 50 μm.

  Subsequently, aluminum was vapor-deposited on the surface A of the biaxially oriented polypropylene film with a crucible vapor deposition machine so that the thickness of the metal vapor-deposited layer was 40 nm, and wound to obtain a metal vapor-deposited polypropylene film.

  Next, a urethane adhesive was diluted with ethyl acetate on the surface B of the metal-deposited polypropylene film with a gravure coater (coating speed 150 m / min) and applied to a thickness of 0.2 μm after drying. It is introduced into a dry dryer, dried at 70 ° C. for 5 seconds under low tension, provided with an anchor coat layer, and further printed using UV ink to obtain a printed film. Next, an adhesive layer for adhering to an adherend such as a bottle is provided on the surface of the metal vapor deposition layer of the printed film, and the metal vapor deposition label of the present invention is wound up in a roll while attaching a separator for releasing the adhesive layer. Got.

  Tables 1 and 2 show the properties of the obtained polypropylene film, metal-deposited polypropylene film, and metal-deposited label.

(Example 2)
The same procedure as in Example 1 was performed except that the B-side of the polypropylene film formed in the same manner as in Example 1 was subjected to corona discharge treatment at a treatment strength of 26 W / m ² / min in air. The results are shown in Tables 1 and 2.

(Example 3)
Except that a polypropylene resin composition containing 2.5% by weight of an ethylene component and 1300 ppm of synthetic silica particles having a particle diameter of 1.8 μm was used as the resin composition constituting the A layer, exactly the same as Example 1. Was carried out. The results are shown in Tables 1 and 2.

Example 4
As the resin composition constituting the B layer, a polypropylene resin composition containing 2000 ppm of crosslinked polymethyl methacrylate particles having a particle diameter of 1.8 μm and 500 ppm of crosslinked polymethyl methacrylate particles having a particle diameter of 3.0 μm was used. Was carried out in exactly the same way as in Example 1. The results are shown in Tables 1 and 2.

(Example 5)
This was carried out in exactly the same way as in Example 1 except that the casting drum temperature was 60 ° C. The results are shown in Tables 1 and 2.

(Example 6)
The same procedure as in Example 1 was performed except that a polypropylene resin composition having a cold xylene-soluble content of 4% by weight was used as the resin composition constituting the C layer. The results are shown in Tables 1 and 2.

(Comparative Example 1)
The surface A of the biaxially oriented polypropylene film formed in the same manner as in Example 1 was 15 W / m ² at a film temperature of 40 ° C. in an atmosphere of a mixed gas of nitrogen and carbon dioxide (carbon dioxide volume ratio 10%). / Min, and then the surface B of the biaxially oriented polypropylene film is 15 W / m ² / m at a film temperature of 40 ° C. in a mixed gas atmosphere of nitrogen and carbon dioxide (carbon dioxide volume ratio 10%). The same procedure as in Example 1 was performed except that the corona discharge treatment was performed for min. The results are shown in Tables 1 and 2.

(Comparative Example 2)
The surface A of the biaxially oriented polypropylene film formed in the same manner as in Example 1 was 29 W / m ² / min at a film temperature of 70 ° C. in a mixed gas of nitrogen and carbon dioxide (volume ratio of carbon dioxide 6%). This was carried out in the same manner as in Example 1 except that the surface B of the biaxially oriented polypropylene film was subjected to a corona discharge treatment of 20 W / m ² / min in air. The results are shown in Tables 1 and 2.

(Comparative Example 3)
Except for using a polypropylene resin composition containing 2.5 ppm by weight of an ethylene component and 2500 ppm of synthetic silica particles having a particle diameter of 1.8 μm as the resin composition constituting the A layer, exactly the same as in Example 1. Was carried out. The results are shown in Tables 1 and 2.

(Comparative Example 4)
The same procedure as in Example 1 was carried out except that a polypropylene resin composition containing 1000 ppm of crosslinked polymethyl methacrylate particles having a particle diameter of 1.8 μm was used as the resin composition constituting the B layer. The results are shown in Tables 1 and 2.

  From Tables 1 and 2, in Examples 1 to 5, the gloss is good, the blocking shearing force is small, the thickness of the deposited metal layer is uniform, the adhesion is strong, the metal deposition blocking is also small, and processing during metal deposition It turns out that it is the thing excellent in property.

  As in Example 6, if the resin composition composing the C layer has too much cold xylene solubles, the resulting polypropylene film has a large thermal shrinkage, so there is a little amount of wrinkles during metal deposition. Although it is a little inferior, it is a level which is satisfactory practically.

  On the other hand, when the specific amount of O / C on the surface of at least one surface of the polypropylene film is not retained as in Comparative Example 1, the metal deposition adhesion and the metal deposition blocking resistance are poor.

  When the value of O / C of the surface A and the surface B of the polypropylene film is too high as in Comparative Example 2, blocking is likely to occur, and generation of defects during metal deposition is observed.

  If the Ra (A) of the polypropylene film is too large as in Comparative Example 3, the glossiness becomes poor and the film thickness of the metal vapor deposition layer becomes nonuniform.

  If the Ra (B) of the polypropylene film is too small as in Comparative Example 4, blocking tends to occur and the metal vapor deposition blocking resistance is poor.

  The present invention is preferably processed as a label by providing a metal vapor deposition layer as described above, and is preferably used to improve the content display / design of plastic bottles and the like, but the application range is not limited thereto.

Explanatory drawing of Example 1 regarding the polypropylene film for labels of this invention, the metal vapor deposition polypropylene film for labels which consists of this, and a metal vapor deposition label.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polypropylene film for labels 1A Metal vapor deposition receiving layer which comprises the polypropylene film for labels 1B Receiving layers, such as printing which comprises the polypropylene film for labels 1C Core layer which comprises the polypropylene film for labels 2 Metal vapor deposition layer 3 Adhesive layer 4 Anchor coat layer 5 UV ink layer 6 Metal vapor deposition label

Claims (4)

The film surface has oxygen atoms bonded to carbon atoms, and the ratio of the number of oxygen atoms to the number of carbon atoms is 0.2 to 0.4 on one surface (surface A), and the other surface (surface B). 0.2-0.3 polypropylene film for labeling, surface A having an average surface roughness (Ra (A)) of 0.012-0.03 μm, surface B having an average surface roughness (Ra (B) ) Is 0.02 to 0.05 μm, and the ratio (Rt (B) / Ra (B)) between the maximum surface roughness (Rt (B)) and Ra (B) of the surface B is 10 to 30 A polypropylene film for labels, characterized in that The polypropylene film for labels is composed of at least three layers in the order of A layer / C layer / B layer, and the resin composition constituting the A layer forming the surface A has an ethylene component and / or a 1-butene component of 0. A polypropylene resin composition containing 5 to 4% by weight of inorganic particles and / or organic particles in an amount of 1000 to 2000 ppm. The resin composition constituting the B layer forming the surface B contains 1500 inorganic particles and / or organic particles. 2. The polypropylene for labels according to claim 1, wherein the resin composition contains ˜3000 ppm, and the cold xylene soluble content of the resin composition constituting the C layer is 0.1 to 3 wt%. the film. A metal vapor-deposited polypropylene film for labels, wherein a metal vapor-deposited layer is provided on the surface A of the label polypropylene film according to claim 1 or 2, wherein the metal vapor-deposited layer has a thickness of 20 to 100 nm, and the surface of the metal vapor-deposited layer. A metal-deposited polypropylene film for labels, characterized by having a gloss of 600 to 900%. The metal vapor deposition label which has a UV ink layer through the anchor-coat layer on the surface B of the metal vapor deposition polypropylene film for labels of Claim 3, and provides the adhesion layer on the surface of the said metal vapor deposition layer.

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