JPH0544129Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Field of Industrial Application) The present invention relates to a laminated film for print lamination, and particularly to a laminated film for print lamination that can be laminated onto printing paper only by thermal adhesion without using a solvent or a separate adhesive. (Prior Art) For the purpose of protecting and beautifying printing paper such as covers of publications, cards, posters, etc., attempts have been made widely to laminate plastic films on the surfaces thereof. Conventionally, such print lamination has mainly been carried out by applying a solvent-type adhesive to a film, drying it, and then bonding it to a printing paper. However, such a method has drawbacks such as residual solvent remaining in the final product and odor, unfavorable working environment, and enormous equipment costs for coating and drying, solvent recovery, etc. Therefore, the development of a laminated film for print lamination that does not require solvents or separate adhesives has been considered, and one currently known example is Japanese Patent Application Laid-open No. 55-93450, which does not require a matte layer. Since it is based on uniaxial stretching, the manufacturing method is limited, and it is not possible to obtain a film with excellent unevenness on the film surface and uniformity of film thickness, and it is not satisfactory in various physical properties such as heat shrinkage characteristics. Furthermore, there was a problem in that the matte properties during thermal bonding tend to disappear. In addition, many of them have insufficient slip properties and anti-locking properties, and no material with sufficient properties is known yet. (Purpose of the invention) The purpose of the invention is to have sufficient adhesive strength, excellent slipperiness and locking resistance, and excellent matting properties that do not lose their matting properties even during thermal bonding. An object of the present invention is to provide a laminated film for thermal adhesive print lamination that can be manufactured by extrusion and does not require adhesive application. (Structure of the invention) The object of the invention is to provide a matte laminated film for print lamination that can be laminated onto printing paper only by thermal adhesion without using a solvent or a solvent-type adhesive. A biaxially stretched polyolefin polymer layer A that has three or more points between 120 and 165°C, a polymer layer B that has one or more melting peak points between 45 and 110°C, and a biaxially stretched polypropylene film. This is achieved by a matte laminated film for print lamination in which the layer C is laminated in an A/C/B arrangement, the total light transmittance is 75% or more, and the glossiness of the polymer layer A is 20 or less. In the polyolefin polymer layer A of the present invention, three or more melting peaks must exist between 120 and 165°C. That is, if there are three or more melting peak vertices, the number of irregularities on the film surface increases and surface scattering increases, resulting in an increased matting effect even when biaxially stretched. Become. In addition, the film has low gloss and high total light transmittance. Further, the polymer layer A needs to be biaxially stretched. That is, when the film is biaxially stretched, the uniformity of the thickness of the unevenness on the film surface is improved, and the maintenance of the matte effect is also excellent. This biaxial stretching can be carried out naturally if a laminated film is manufactured by coextrusion as described later, and it also improves the film's various physical properties, including its strength and heat shrinkage properties. It becomes something. Specific examples of the polymer layer A include ethylene,
mixtures of polymers of propylene, other α-olefins, ethylene and propylene and/or other α-olefins;
These layers include a copolymer with olefin, a mixture of the above copolymers, and a mixture of the above copolymer and a polymer of ethylene, propylene, or other α-olefin. Among these layers, a layer consisting of either of the following is preferable. Also, more preferably, among the above polymer layers,
Ethylene-propylene block copolymer (hereinafter referred to as
A layer containing 60 to 95% by weight of BEPC (abbreviated as BEPC) and 40 to 5% by weight of at least one selected from polyethylene and polypropylene is desirable, and the layer is polymerized so that three melting peaks occur at 120 to 165°C. A layer of ethylene propylene block copolymer (hereinafter abbreviated as BEPC-3) is particularly preferred.
This BEPC-3 is made of high-density polyethylene (hereinafter referred to as
(hereinafter referred to as HDPE), medium density polyethylene (hereinafter referred to as
MDPE), linear low density polyethylene (hereinafter referred to as
It may be even more preferable to blend it with LLDPE) etc. The amount of ethylene in these BEPC and BEPC-3 is 10 to 40 wt% based on the total copolymer weight, preferably
It is 15-30wt%. In the case of a blend system, the amount of ethene is 20 to 50 wt%. Inorganic particles (kaolin,
Clay, microdol, silica, zeolite, etc. having an average diameter of 0.2 to 10 μm may be added in an amount of 10 to 40 wt %, and in this case, it also provides drawing properties. The surface gloss of the polymer layer A formed into a laminated film is 20 or less, preferably 16 or less. If the value is higher than this value, the diffused reflection will be low and the matting properties will be poor. Polymer layer B with one or more peaks of melting peak between 45 and 110°C means
A layer of a polymer having at least one between 110° and specifically (meth) such as polyethylene, ethylene-butene-1 copolymer, ethylene and acrylic acid, methacrylic acid, methyl methacrylate, etc.
Examples include copolymers with acrylic esters, copolymers of ethylene and maleic anhydride, terpolymers of the copolymer components and maleic anhydride, ethylene-vinyl acetate copolymers, and mixtures thereof. . The most preferable polymer for layer B is one in which the melting peak between 45 and 110°C accounts for 80 to 100% of the total peak, but it may also account for 50% or more, and other α- It may be used in combination with an olefin polymer. Biaxially oriented polypropylene film contains propylene as the main monomer component (60% by weight or more, preferably
80% by weight or more) (including blends with olefin copolymers, etc.), and may be stretched either simultaneously or sequentially. The essence of the lamination of these layers is that the A/C/B arrangement, that is, the biaxially stretched polypropylene film C is used as the intermediate layer. Lamination methods include a coextrusion method, a method of laminating after uniaxial stretching, and a method of laminating after biaxial stretching, but coextrusion is preferred. When a coextrusion method is used, the polymer layer A is naturally also necessarily biaxially stretched. The laminated film thus obtained must have a total light transmittance of 75% or more; if it is less than 75%, the printed material on the base becomes difficult to see and becomes dull when printed laminated. The laminated film of the present invention is thermally bonded to printing paper, and this thermal bonding is performed with layer B in contact with the printing paper. The term "printed paper" as used herein refers to a material printed on natural paper (high-quality paper, art paper, coated paper, etc.), and natural paper is preferred. (Effects of the invention) The laminated film for print lamination of the present invention can be adhered to printing paper only by thermal adhesion and maintain sufficient adhesive strength, thus simplifying the process and reducing equipment costs, maintenance and operation costs, etc. It will be cheaper. Further, due to the presence of the polymer layer A, fine irregularities are formed on the surface, which has a matte property and does not disappear even when thermally bonded, giving the printed matter a more luxurious feel. Furthermore, it has excellent anti-locking properties and slip properties. (Measurement method) (1) Vertex of melting peak Perkin-Elmer differential scanning calorimeter model
So-called second-run melting occurs when a 5 mg sample is heated to 280°C at a heating rate of 20°C/min, held for 5 minutes, cooled at the same rate, and heated again using the DSC-2 model. Take a curve. The apex of the melting peak refers to the inflection point or shoulder-like point of this curve, and the temperature difference between the apexes is preferably 5° C. or more. (2) Total light transmittance Measured according to JIS-K6714. (3) Glossiness This is a measurement method (GS-60°) in which both the incident angle and acceptance angle are 60 degrees according to method 2 shown in JIS-Z8741. (4) Slip coefficient Two samples were conditioned for 24 hours in a room at 20°C and 65% RH.
Move one sample at a speed of 150 mm/min with a load of g, read the resistance value, and calculate the resistance value g/
It is shown as a calculated value of 200g. (5) Blocking shear force (evaluation of blocking resistance) Sample films of 3 cm width x 10 cm length were stacked over a length of 4 cm, and a load of 40 g/cm ² was applied in an atmosphere of 40°C and 80% RH. After leaving it for 24 hours, measure the force required for shear peeling using a tensile tester. The smaller the value, the better the blocking resistance. Next, examples and comparative examples will be shown. Example 1 As polymer layer C, M1=2 at 230°C
g/10 minutes of polypropylene into one extruder as polymer layer A, the top of the melting peak is 122℃,
BEPC polymerized at three points at 142℃ and 152℃
-3 is fed to another extruder, melt extruded at 280℃, wrapped around a cooling drum at 40℃, and then
An unstretched sheet of 670 μm (PP of base material approximately 570 μm) was obtained. This sheet was stretched 4 times in the longitudinal direction while heating to 120°C, and then cooled to form a uniaxially stretched film.
Next, as polymer layer B, a melting peak temperature of 90°C
The ethylene vinyl acetate copolymer was melted and discharged from an extruder heated to 180°C, laminated on the uniaxially stretched film, and cooled and solidified on a cooling roll kept at 30°C. The film was further stretched about 10 times in the width direction in a tenter heated to 170°C, and then heat treated at 155°C while giving a relaxation rate of 5%. Thus, the total thickness
25μm, polymer layer A thickness 3μm, polymer layer B
A matte laminated film for print lamination with a thickness of 5 μm and a polymer layer C of 17 μm was obtained. Layer the polymer layer B of this matte laminated film for print lamination on the printing surface of the printing paper and heat it at 110°C.
Linear pressure 40Kg/cm, 25m/
The printed laminate was laminated under heat and pressure at a speed of 1 minute to obtain a printed laminate with a matte finish. Example 2 The apex of the melting peak of polymer layer A was 123°C,
BEPC polymerized at three points at 148℃ and 156℃
Example 1 was carried out in the same manner as in Example 1, except that the polymer layer B was a low-crystalline ethylene-butene-1 random copolymer with a melting peak temperature of 70°C. Polymer layer B has a melting peak temperature of 95℃ and 190℃.
Melt flow rate (MFR) at ℃ 20
The same procedure as in Example 1 was carried out except that the ethylene-methyl methacrylate copolymer was used at g/10 min. Comparative Examples 1 and 2 The same procedure as Example 2 was carried out except that the polymer layer A was changed as follows. Comparative Example 1 BEPC-3 polymerized so that the melting peaks were at three points: 108°C, 129°C, and 148°C. Comparative Example 2 Ethylene-propylene random copolymer polymerized so that the apex of the melting peak is only at 140°C. Comparative Example 3 Except that polymer layer B was an ethylene-propylene random copolymer with a melting peak temperature of 130°C,
It was carried out in the same manner as Comparative Example 2. Comparative Example 4 The apex of the melting peak of polymer layer A was 123℃, 160℃
The same procedure as in Example 1 was carried out except that BEPC was polymerized at two points at ℃. These results are summarized in the table below. Example 1
and BEPC as polymer layer A as shown in 2.
By using -3, a film with low gloss and excellent matte properties can be obtained even when biaxially stretched, and the total light transmittance is high, so it has excellent visibility in printing, and is suitable for use as a film for print lamination. It became suitable. In addition, because the lowest melting peaks (122 and 123°C) are on the high temperature side, the surface roughness does not collapse even with the heat during lamination, and it was found that the matte maintenance property is excellent. Since the surface of the polymer layer A was roughened, the sliding property with the polymer layer B and the blocking resistance were also good. In addition, the adhesive strength (peel strength) with printing paper is 150, 110 and 120, respectively.
It was strong at g/cm. In Comparative Example 1, the melting peak of polymer layer A was 3
Although there were some spots, the lowest peak (108°C) was on the low temperature side, so the matte properties were lost during lamination, making the film unsuitable for print lamination. In Comparative Examples 2 and 3, the surface of the polymer layer A was not roughened at all, and films without matte properties were obtained. Furthermore, the slip properties and anti-blocking properties were also poor. Furthermore, in Comparative Example 3, since the melting peak temperature of polymer layer B was high, it did not adhere to the printing paper at all. In Comparative Example 4, the melting peak of polymer layer A was 2
Because of the presence of only dots, even though biaxial stretching was used, only a film with low surface roughness, insufficient matting properties, and inferior slipping and blocking properties could be obtained.

【table】

【table】 [Brief description of the drawings]

FIG. 1 is a sectional view of a laminated film for print lamination according to the present invention, and FIG. 2 is a sectional view showing a state in which the laminated film is laminated onto printing paper. 1... Polymer layer A, 2... Biaxially stretched polypropylene film, 3... Polymer layer B, 4... Printing ink, 5... Paper.

Claims (1)

[Scope of utility model registration request] A matte laminated film for print lamination for laminating on printing paper only by thermal adhesive without using a solvent or solvent-type adhesive, which has three or more melting peaks between 120 and 165°C, and the top of the biaxially stretched olefinic polymer layer A and the melting peak are between 45 and 95°C.
The polymer layer B and the biaxially oriented polypropylene film layer C are laminated in an A/C/B arrangement, and the total light transmittance is 75% or more, and the gloss of the polymer layer A is 75% or more.
Matte laminated film for printed lamination with a rating of 20 or less.