JPS64987B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polypropylene composition for producing a film with excellent printability, transparency and antistatic properties. Polypropylene film has traditionally been widely used as a packaging material, mainly in the food field.
Ink using organic solvents such as toluene and ethyl acetate is used for printing. These organic solvents have a good affinity with the polypropylene film that is the printing base material and cannot be sufficiently removed in the drying process. As a result, organic solvents migrate into the food products that are packaged, posing a hygiene problem. Because of this problem, several improvement methods have been proposed. For example, a method of applying and drying a resin composition emulsion after forming a film (Japanese Unexamined Patent Publication No. 49-1989)
131265), a method of laminating organic titanate-containing polymers (Japanese Patent Application Laid-Open No. 48-44362), and a method of corona discharge treatment of a film in a nitrogen atmosphere (Japanese Patent Application Laid-open No. 71182-1982). However, although these methods are certainly effective in terms of printability for cellulose-based inks,
It cannot be used with water-based or alcohol-based inks due to poor water resistance, or it may cause defects on the film because it is unstable against moisture in the air, or it may have poor operability. There is a problem. As a method to overcome this drawback, a method of laminating layers containing an acrylic acid copolymer (Japanese Patent Publication No.
18385) has been proposed. Although this method is quite effective, it does not necessarily satisfy the recent demands of the market, and there are expectations for a method that further improves printability and antistatic properties. The present invention was achieved as a result of research from this point of view, and is a polypropylene resin composition imparted with printability characterized by comprising the following components (a) to (c). (a) 98.5 to 60% by weight of crystalline polypropylene (b) A copolymer consisting of 80 to 95% by weight of ethylene and one or more compounds represented by the following formula (1)
0.05-10% by weight (However, R is H or CH ₃ , X is OH,
OCH ₃ , OC ₂ H ₅ , OC ₂ H ₄ N (CH ₃ ) ₂ , OC ₂ H ₄ N
( _C2H5 ) _{2 ,}

[Formula] OCH ₂ CH ₂ OH, or NH ₂ . ) (c) 1 to 30% by weight of ethylene-butene copolymer The crystalline polypropylene of component (a) used in the present invention may be a propylene homopolymer or
More than 70% by weight of propylene and ethylene, butene,
Copolymers with other olefins such as pentene, 4-methylpentene, hexene, etc., or these polymers that have been chlorinated, oxidized, sulfonated, or modified with unsaturated organic acids such as acrylic acid and maleic anhydride. etc. are suitable. Those having an isotactic index (II) representing crystallinity of 60 or more, preferably 80 or more, particularly 90 or more are used. A particularly preferred application example of the composition of the present invention is a film in which the composition of the present invention is laminated on at least one side of a polypropylene film, and furthermore, a film obtained by biaxially stretching the same. A propylene homopolymer having a value of 90 or more is preferred. MFR is not limited as long as it can be molded, but preferably 0.1 to 150 g/10 minutes, particularly 1 to 20 g/10 minutes for film applications. Next, a copolymer consisting of 80 to 95% by weight of ethylene as the component (b) above and one or more compounds represented by the following formula (1). (However, R is H or CH ₃ , X is OH,
OCH ₃ , OC ₂ H ₅ , OC ₂ H ₄ N (CH ₃ ) ₂ , OC ₂ H ₄ N
( _C2H5 ) _{2 ,}

[Formula] OCH ₂ CH ₂ OH, or NH ₂ . ) means ethylene-(meth)acrylic acid copolymer,
Ethylene-methyl (meth)acrylate copolymer,
Ethylene-(meth)ethyl acrylate copolymer,
Ethylene-(meth)acrylic acid-2-(dimethylamino)ethyl copolymer, ethylene-(meth)acrylic acid-2-(diethylamino)ethyl copolymer,
They are ethylene-glycidyl (meth)acrylate copolymer, ethylene-hydroxyethyl (meth)acrylate copolymer, or ethylene-(meth)acrylic acid amide copolymer. The preferred ethylene content of this copolymer is from 85 to
It is 90% by weight. In addition, the ethylene-
Butene-based copolymers generally have a butene content of 1 to 1.
50% by weight, preferably 5-20% by weight. In addition to ethylene and butene, this copolymer may contain up to 30% by weight, preferably up to 10% by weight of other olefins (propylene, pentene, hexene, 4-methylpentene, etc.). The blending ratio of these three components is as follows: (a) component: 98.5 to 60% by weight, preferably 96.5 to 88% by weight (b) component: 0.05 to 10% by weight, preferably 0.5 to 2% by weight (c) component: 1 -30% by weight, preferably 3-10% by weight. Other thermoplastic resins, various stabilizers, lubricants, antistatic agents, antiblocking agents, pigments, etc. may be added to the composition of the present invention within the range that does not impair the effects of the invention. The composition of the present invention can be obtained by mixing and kneading each component in a kneading machine such as a roll, a Banbury mixer, a Brabender plastograph, or an extruder. It is also possible to prepare a master batch containing any one of the three components at a high concentration, dilute it, and use it. The composition of the present invention has improved printability, especially with water-based inks, and has excellent transparency and antistatic properties, so it can be applied to various molded products, but it is most effective to use it in the form of a film. be. The film may be a single layer film, but
Particularly preferred is a polypropylene film laminated with a film of the composition of the present invention on at least one side, or more preferably biaxially stretched. Such a film can be obtained by a conventional film forming method, coextrusion method, lamination method, or stretching method. The film may be subjected to surface activation treatments such as corona discharge treatment and flame treatment. The film obtained in this way has excellent printability with not only cellulose ink but also water-based ink with acrylic resin as a binder, compared to the film obtained by subjecting ordinary polypropylene to corona discharge treatment. Therefore, there are no hygiene problems. Next, as will be explained in Examples, each test in the Examples was conducted using the following measurement method. (1) Film transparency (HAZE) The surface and interior were measured in accordance with ASTM-D1003-61. (2) Wet tension Measured in accordance with ASTM-D2578-67. (3) Printability (a) Cellophane tape peeling test Commercially available 18 mm wide cellophane tape was placed 15 cm on the printing surface.
Paste it in two rows with the same length, press it back and forth 5 times with a rubber roller so that a linear pressure of 3 kg/cm is applied, and then peel it off at 90 degrees at a speed of 50 cm/sec, and the printing ink will not peel off. The area remaining in the area was evaluated as follows. More than 95% remains; ◎ 80% 〃 ; 〇 50% 〃 ;△ 〃 Only less than 〃 remains; 10 left and right hands vertically
After kneading, the printing ink remaining without falling off was evaluated as follows. When massaging your hands,
Rub together with some force, but not enough to stretch or tear the film. Does not fall off at all; ◎ Only a small portion falls off; 〇 Quite a lot falls off; △ Most of it falls off;
A voltage of 10KV was applied to the sample for 2 seconds while rotating the sample.
After applying the voltage for a minute, the voltage was turned off and the spindle was rotated for an additional 3 minutes. At this time, a recorder-type potentiometer (full scale 25 to 50 mV) connected to the power receiving part of this device records the increase and decay curve of the charged voltage of the sample from the start of voltage application. From this curve, the charged voltage when voltage application is stopped is
amV and the charged voltage after 3 minutes bmV
The attenuation rate was calculated using the following formula. Attenuation rate=ab/a×100 Further, the time (seconds) until the charged voltage becomes a/2 mV due to attenuation after the voltage application was stopped was defined as the half-life. The copolymer of component (b) used in the examples was polymerized in the following manner. Polymerization example 1 Dissolve ethylene and 5 kg of acrylic acid in ethyl acetate in an autoclave with a capacity of 1.2 and L/D5.
and 120 g of t-butylperoxyisobutyrate were dissolved in n-hexane and diluted with 10
The solution was injected at a pressure of 2200 Kg/hr, 1.2/hr and 0.5/hr, respectively.
Polymerization was carried out at a rate of Kg/cm ² and a temperature of 220±5°C. The ethylene-acrylic acid copolymer obtained by washing and drying is
MFR (190°C, 2.16 kg load) was 10 g/10 minutes, acrylic acid content was 8% by weight, and specific gravity was 0.940. Polymerization Example 2 In the same manner as in Polymerization Example 1, an ethylene-ethyl acrylate copolymer was obtained. However, in Polymerization Example 1, acrylic acid was replaced with ethyl acrylate, and the injection rate of each component was changed to ethylene.
42Kg/hr, ethyl acrylate solution 0.8/hr, t
-Butyl peroxyisobutyrate solution 0.4/
hr. The obtained ethylene-ethyl acrylate copolymer had an MFR of 6.8 g/10 minutes and an ethyl acrylate content of 5.6.
The weight percent and specific gravity were 0.930. Polymerization Example 3 In the same manner as in Polymerization Example 1, an ethylene-2-(dimethylamino)ethyl methacrylate copolymer was obtained. However, in Polymerization Example 1, acrylic acid was replaced with 2-(dimethylamino)ethyl methacrylate,
The injection rate of each component was 40 kg/hr of ethylene and 0.8 kg/hr of 2-(dimethylamino)ethyl methacrylate solution.
hr, t-butyl peroxyisobutyrate solution
It was set as 0.5/hr. The polymerization pressure was 2400 Kg/cm ² and the temperature was 230±5°C. The obtained ethylene-2-(dimethylamino)ethyl methacrylate copolymer had an MFR of 5.5 g/10
The content of 2-(dimethylamino)ethyl methacrylate was 4.8% by weight, and the specific gravity was 0.935. Polymerization Example 4 In Polymerization Example 1, acrylic acid was replaced with glycidyl methacrylate, and the injection rate of each component was changed to ethylene 32.5 Kg/hr and glycidyl methacrylate solution.
Polymerization was carried out at a pressure of 2400 Kg/cm ² and a temperature of 260±5° C. using a trace amount of oxygen instead of the t-butyl peroxyisobutyrate solution as a catalyst. The obtained ethylene-glycidyl methacrylate copolymer had an MFR of 4.8 g/10 minutes, a glycidyl methacrylate content of 2.4% by weight, and a specific gravity of 0.930. Polymerization Example 5 In Polymerization Example 1, acrylic acid was replaced with hydroxyethyl acrylate, and the injection rate of each component was changed to 38 kg/hr of ethylene and hydroxyethyl acrylate solution.
1.2/hr, t-butylperoxyisobutyrate solution 0.4/hr, pressure 2300Kg/cm ² , temperature
Polymerization was carried out at 230±5°C. The obtained ethylene-hydroxyethyl acrylate copolymer had an MFR of 6.5 g/10 minutes, a hydroxyethyl acrylate content of 4.2% by weight, and a specific gravity of 0.935. Polymerization Example 6 In Polymerization Example 1, acrylic acid was replaced with acrylamide, and the injection rate of each component was changed to 46.5 kg of ethylene/46.5 kg of ethylene.
hr, acrylamide solution 0.6/hr, t-butylperoxyisobutyrate solution 0.2/hr,
Polymerization was carried out at the same pressure and temperature of 240±8°C. The obtained ethylene-acrylamide copolymer had an MFR of 8.3 g/10 minutes, an acrylamide content of 3.6% by weight, and a specific gravity of 0.928. Example Predetermined amounts of the above components (b) and (c) were blended into crystalline polypropylene (Mitsubishi Noblen FL6S manufactured by Mitsubishi Yuka Co., Ltd.; MFR 2.0 g/10 minutes) as shown in Table 1, and the mixture was heated in an extruder (240°C). ), then separately melt-knead only polypropylene (FL6S) in an extruder (250℃), extrude both of them into a sheet from a two-layer die, melt-bond them, cool and solidify with a mirror roll, and then unstretch. Got a sheet. This sheet has a 1mm polypropylene layer on one side.
50μ resin composition is laminated. Next, heat this sheet to 120℃ and roll it vertically for 5 minutes.
Stretched twice, then in the transverse direction while heating to 165℃
After stretching 10 times and heat-treating at 155°C for 10 seconds, the laminated surface of the resin composition was subjected to corona discharge treatment (80W min/m ² ) and wound up. This film was printed with printing ink for cellophane (CCST-62 white, manufactured by Toyo Ink Mfg. Co., Ltd.) using a Meyer bar. On the other hand, water-based ink (JW34 Aqua Color 152 Red/61 White manufactured by Toyo Ink Manufacturing Co., Ltd.) was printed using a gravure roll, and the printability of each was evaluated. In addition, a single-layer biaxially stretched polypropylene (FL6S) film was formed and wound in the same manner as above, and evaluated in the same manner. Next, HAZE, wetting tension and antistatic properties of these films were measured. These results are shown in Table 1. In the table, the symbols indicate the following contents. EM1; Copolymer polymerized in Polymerization Example 1 EM2; Copolymer EM3 polymerized in Polymerization Example 2; Copolymer EM4 polymerized in Polymerization Example 3; Copolymer EM5 polymerized in Polymerization Example 5; Polymerized copolymer EM6; Copolymer N2540R polymerized in Polymerization Example 6; Ethylene-butene copolymer manufactured by Mitsui Petrochemical Industries, Ltd. (Neozex 2540R, specific gravity 0.925, MFR 4.0 g/10 min) GPX-1; UCC Company manufactured ethylene-butyne copolymer (L-LDPE GPX-1, specific gravity 0.918,
MFR1.0g/10min) EY-40H; High-density polyethylene manufactured by Mitsubishi Yuka Co., Ltd. (HDPE EY-40H, specific gravity 0.952,
MFR1.5g/10min) MODIC: Maleic anhydride graft modified polypropylene manufactured by Mitsubishi Yuka Co., Ltd. (MODIC P-
300F, specific gravity 0.89, MFR 1.0g/10 minutes)

[Table] Examples Polypropylene used in Examples and Polymerization Example 1
89, 1, and 10% by weight of EM1 manufactured by Mitsui Petrochemical Industries, Ltd. and Tafmer A, an ethylene-butene copolymer manufactured by Mitsui Petrochemical Industries, Ltd., were blended, respectively, and a biaxially stretched film with polypropylene was formed in the same manner as in the example. . This film was printed with printing ink for cellophane, and the printability was evaluated in a hand kneading test, and it was found to be very good.

Claims (1)

[Scope of Claims] 1. A polypropylene resin composition imparted with printability, characterized by comprising the following components (a) to (c). (a) 98.5 to 60% by weight of crystalline polypropylene (b) A copolymer consisting of 80 to 95% by weight of ethylene and one or more compounds represented by the following formula (1)
0.05-10% by weight (However, R is H or CH ₃ , X is OH,
OCH ₃ , OC ₂ H ₅ , OC ₂ H ₄ N (CH ₃ ) ₂ , OC ₂ H ₄ N
(C ₂ H ₅ ) ₂ , [Formula] OCH ₂ CH ₂ OH, or NH ₂ . ) (c) 1 to 30% by weight of ethylene-butene copolymer