JPS6235412B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an olefin resin composition that provides a film with excellent light resistance. It is known that a biaxially oriented resin film containing 1 to 25% by weight of an inorganic filler has writability (see US Pat. No. 3,154,461). In addition, on the biaxially stretched film base layer, clay,
A multilayer film with excellent printability and writability is also known, which has a structure in which uniaxially stretched films made of olefinic resin containing fine inorganic powders such as diatomaceous earth, calcium carbonate, and titanium oxide are laminated (Japanese Patent Publication No. 1973-
Publication No. 40794). In this laminated film, the base layer made of a biaxially stretched film provides tensile strength against tearing of the film, and the surface layer made of a uniaxially stretched film provides offset printability and writability. In these films having the printability and writability described above, the use of calcium carbonate as the inorganic fine powder means that the Mohs hardness of calcium carbonate is 3.
This has the advantage that the wear of dies of film forming machines, plate materials of roll printing machines, and blades of processing machines such as cutting and punching machines is extremely small. Further, even when calcium carbonate is mixed into ink such as offset ink or gravure ink, the fluidity of the ink does not decrease, and beautiful printed matter without uneven printing ink transfer can be obtained. Furthermore, offset printing ink dries faster when it is alkaline, and using calcium carbonate as fine powder leads the ink to the alkaline side, which has the effect of accelerating the drying properties of the offset printing ink. Therefore, in a film containing inorganic fine powder that can be printed and written on, it is useful to use calcium carbonate as the fine powder. However, the laminated film, which has a single-layer biaxially stretched film or uniaxially stretched film containing calcium carbonate as a surface layer and a biaxially stretched film as a base layer, has low light resistance, and if left outdoors for a long period of time, it will be exposed to UV rays. This has the disadvantage that the olefin resin deteriorates and the strength of the film is significantly reduced. In order to improve this light resistance, it is conceivable to incorporate titanium oxide, which is an ultraviolet absorber or ultraviolet absorbing substance and is also an extender pigment. The use of titanium oxide as a light fastness improver is also useful in terms of improving the whiteness of the film. However, the addition of titanium oxide only improves the light resistance by at most twice as much as when it is not added. It is known that a UV absorber is used in combination with titanium oxide in a resin film containing fine powder of calcium carbonate (see Example 6 of Japanese Patent Publication No. 3902/1983). The component of Tinuvin 326 (trade name of Shiraishi Kogyo) described here is 2(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, which is oxidized with Even if both titanium and titanium are blended into the olefin resin, the light resistance will only be improved by about 2 to 4 times at most compared to the case where both are not blended. In order to improve the light resistance of olefin-based resin compositions containing calcium carbonate fine powder, the present inventors have developed bis(2,2,6,6) together with titanium oxide.
-Tetramethyl-4-piperidyl) sebacate, it was surprisingly found that the light resistance was improved by about 8 times or more compared to the case where neither was blended, and the present invention was completed. That is, the present invention comprises: (A) 100 parts by weight of olefin resin (B) 3 to 300 parts by weight of fine calcium carbonate powder (C) 1 to 60 parts by weight of fine titanium oxide powder (D) Bis(2,2,6, 6-tetramethyl-4-
piperidyl) sebacate 0.05 to 5 parts by weight The present invention provides a resin composition characterized in that the components (A) to (D) are blended in the above formulation. In the present invention, the above-mentioned olefin resin includes homopolymers of olefins such as ethylene, propylene, butene-1, copolymers of two or more of these olefins, ethylene/vinyl acetate copolymers,
Examples include ethylene/methyl acrylate copolymer. Among these, polypropylene and high-density polyethylene are preferred from the viewpoint of strength. These may be used alone or in combination of two or more. Next, the calcium carbonate blended into the olefin resin preferably has an average particle size of 0.3 to 5 μm, and 3 to 300 parts by weight per 100 parts by weight of the olefin resin.
It is used in a proportion of 10 to 100 parts by weight, preferably 10 to 100 parts by weight. If the amount is less than 3 parts by weight, the offset printability and writability of the film obtained by molding the composition will not be sufficient. Further, the fine titanium oxide powder to be blended into the olefin resin preferably has an average particle size of 0.05 to 5 μm. The titanium oxide powder is blended in an amount of 1 to 60 parts by weight, preferably 3 to 25 parts by weight, per 100 parts by weight of the olefin resin. If the amount is less than 1 part by weight, the light fastness will not be improved sufficiently, and even if it exceeds 60 parts by weight, it is difficult to expect a further dramatic improvement in the light fastness and whiteness of the resulting film, and the price will be reduced. It is not economical to use a large amount of expensive titanium oxide. And screws (2,
2,6,6-tetramethyl-4-piperidyl) sebacate is used in an amount of 0.05 to 5 parts by weight, preferably 0.5 to 1 part by weight, based on 100 parts by weight of the olefinic resin. The resin composition of the present invention can be made into a film by T-die molding or inflation molding, and can be used as synthetic paper having printability and writability. A stretched film obtained by further uniaxially or biaxially stretching this film has a structure having many fine voids inside, and has improved opacity, whiteness, and paper-like feel. The uniaxially stretched product can be used not only for gravure printing but also for offset printing, and can be written on with a pencil as well as with oil-based or water-based ink. This means that the film surface has five minute cracks.
This seems to be due to the large number of particles/mm ² or more. In addition, the biaxially stretched product can be used for writing with Shinshu-like gloss,
It is a printable film. A uniaxially oriented single layer alone has directional properties in terms of stiffness, tensile strength, and tear strength, and its strength in the direction perpendicular to the stretching direction is weak. Therefore, in practice, a uniaxially oriented film is used as the surface layer, and a biaxially oriented film or a stretched film is used as the surface layer. It is preferable to use a multilayer film structure in which a base layer is a film that is not coated. The base material layer can also contain inorganic fine powders such as titanium oxide and calcium carbonate. When the purpose is to make a printing film, the inorganic fine powder is used in an amount of 15 to 60 parts by weight, and when the purpose is to make a tracing paper that requires translucency, it is used in an amount of 25 parts by weight or less. The structure of this multilayer film is that on one side of the base layer,
A two-layer film with a structure in which the surface layers are laminated together,
Even if it is a three-layer film with a structure in which a surface layer is integrally laminated on both sides of the base layer, a film with three or more layers in which another type of film is further integrally laminated on the back side of the above-mentioned two-layer film. It's okay to be. To produce this laminated resin film, calcium carbonate, titanium oxide, bis(2,2,6,6-
The compositions forming the surface layer and the base layer made of the olefinic resin composition of the present invention containing tetramethyl-4-piperidyl) sebacate were melt-kneaded using separate extruders, and then melt-kneaded using the same extruder. A laminated film is produced by supplying the film to a substrate and coextruding it by an inflation method or a T-die method, and then sequentially or simultaneously biaxially stretching the film. Further, the olefin-based film of the present invention is prepared by pre-stretching a film obtained by T-die molding the resin composition forming the base layer in a uniaxial direction, and then forming a surface layer on the stretched film. It is manufactured by melt-laminating a resin composition film and then stretching it in a direction perpendicular to the stretching direction. In the latter manufacturing method, if the surface layer is so thin that extrusion molding or stretch molding is expected to be difficult, the olefin resin composition of the present invention forming the surface layer and the inorganic fine powder content may be small or not at all. It is preferable to coextrude an olefin-based resin composition that does not contain the olefin resin composition and melt-laminate it onto the stretched film of the base layer. The stretching is performed at a temperature lower than the melting point of the olefin resin, and the stretching ratio is 1.3 times or more, preferably 2.5.
~10 times (in the axial direction) and an area magnification of 5 to 50 times. By stretching, a large number of fine pores are formed inside the surface layer and the base layer, giving the laminated film a paper-like texture. Further, when the surface layer is a uniaxially stretched product, surface cracks mainly caused by fine powder are also formed on the surface, and absorption of offset printing ink is improved. The thus obtained laminated film has good printability and writability, excellent light resistance, and has the texture of pulp paper with high whiteness. In addition to the surface layer, the base material layer, either layer, or both layers may contain titanium oxide, bis(2, 2, 6,
In addition to 6-tetramethyl-4-piperidyl) sebacate, organic fillers, fibrous substances, antioxidants,
It may contain a dispersant, an antistatic agent, a lubricant, etc. In particular, in the composition of the invention, oleic acid
When blended at a ratio of 0.05 to 5 parts by weight per 100 parts by weight of olefin resin, a composition with good dispersion of calcium carbonate and titanium oxide in the olefin resin and a small change in hue is obtained. Obtainable. In addition, when three or more of the following antioxidants (a) to (c) are blended in the proportions shown below to 100 parts by weight of olefin resin, it is effective against heat or gases such as nitrogen oxides. It has the advantage of producing a resin film that does not change in hue. Antioxidant: (a) 2,6-di-tert-butyl para-cresol 0.05~
1 part by weight. (b) 0.05 to 1 part by weight of an antioxidant selected from tri(mono- and/or di-nonylphenyl) phosphite and distearyl pentaerythritol diphosphite. (c) Antioxidant selected from tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate. agent 0.05 to 1 part by weight. The present invention will be explained in more detail with reference to Examples below. In addition, all formulation parts in the examples are based on weight. Example 1 100 parts of polypropylene “Mitsubishi Noblen MA4” (trade name) manufactured by Mitsubishi Yuka Co., Ltd., 20 parts of calcium carbonate with an average particle size of 1.5μ, 10 parts of rutile-type titanium oxide, 2.
6-di-tert-butyl-4-methylphenol 0.1
part, octadecyl 3,5-di-tert-butyl-4-
Hydroxyphenyl) propionate 0.1 part, distearyl pentaerythritol diphosphite
0.1 part, 0.5 part of oleic acid and bis(2,2,
A composition consisting of 0.4 part of 6,6-tetramethyl-4-piperidyl) sebacate was kneaded and melted using an extruder. This melt was introduced into a die, extruded into a sheet, and then cooled. The obtained sheet was heated to 150°C, stretched 4 times in the machine direction, then 10 times in the transverse direction, and cooled. The obtained biaxially stretched film with a wall thickness of 80 μm was white, opaque, and pearlescent, and had a pulp paper-like texture that was capable of gravure printing and writing. Many minute voids were formed inside this film. Comparative Example 1 2(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5 instead of bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate
A biaxially stretched film with pearlescent luster was obtained in the same manner as in Example 1 except that chlorobenzotriazole was used. Comparative Example 2 In Example 1, titanium oxide and bis(2,
A biaxially stretched film was obtained in the same manner except that 2,6,6-tetramethyl-4-piperidyl) sebacate was not blended. Comparative Example 3 A biaxially stretched film was obtained in the same manner as in Example 1, except that a resin composition containing no bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate was used. Example 2 Polypropylene “Noblen MA” manufactured by Mitsubishi Yuka Co., Ltd.
-6” (product name) 90 parts, Mitsubishi Yuka Co., Ltd. high-density polyethylene “Yukalon Hard EY-40” (product name) 10
parts, 0.8 parts of titanium oxide with an average particle size of 1μ, clay 15
As antioxidants, “Yoshinox BHT” (trade name) manufactured by Yoshitomi Pharmaceutical Co., Ltd., “Mark-329” (trade name) manufactured by Adeka Argus Chemical Co., Ltd., and Ciba Geigy Co., Ltd.
After melting and kneading using an extruder a composition consisting of 0.1 part each of "Irganox-1076" (trade name) manufactured by Kao Soap Co., Ltd. and 0.1 part of oleic acid "Lunatsuku" (trade name) manufactured by Kao Soap Co., Ltd. as a dispersant. , from Dai
It was extruded into a sheet at a temperature of 200°C and the sheet was cooled to about 50°C. This sheet is then heated to approximately 135℃.
After heating, the film was stretched 4 times in the longitudinal direction using the difference in circumferential speed between the roll groups. Separately, polypropylene (Mitsubishi Noblen MA-
6) 100 parts, 10 parts of titanium oxide with an average particle size of 1μ, 80 parts of calcium carbonate with an average particle size of 1.5μ, bis(2,
0.4 parts of 2,6,6-tetramethyl-4-piperidyl) sebacate, Yoshinox as an antioxidant
A composition containing BHT, Mark 329, and Irganox-1076 in a ratio of 0.1 part each and 0.1 part of oleic acid was melt-kneaded using two other extruders, and the mixture was melt-kneaded using a die at a temperature of 200°C. Laminate on both sides of the vertically stretched sheet, cool to a temperature 20℃ higher than room temperature, and then heat to approximately 155℃.
The biaxially stretched film of the intermediate layer (base material layer) was reheated to 70 μm in thickness, stretched 8 times in the transverse direction using a tenter, and then passed through an oven at 160°C to heat set it. A film with a three-layer structure in which the thickness of the uniaxially stretched film of the front and back layers was 10 μm was obtained, and the film had excellent printing and writing properties. The stretched film obtained in this way has good printability and writability, does not discolor even when stored outdoors or at high temperatures for a long time, and has the texture of pulp paper with a high degree of whiteness. It was a film with Comparative Example 4 In Example 2, titanium oxide and bis(2,2,6,6-
A laminated film was obtained in the same manner except that a resin composition containing no tetramethyl-4-piperidyl) sebacate was used. Comparative Example 5 2(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5 instead of bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate
-A laminated film was obtained in the same manner as in Example 2 except that chlorobenzotriazole was used. Comparative Example 6 In Example 2, bis(2,2,6,6-tetramethyl-
A laminated film was obtained in the same manner except that a resin composition containing no 4-piperidyl) sebacate was used. Comparative Example 7 A laminated film was obtained in the same manner as in Example 2, except that a resin composition containing no titanium oxide was used as the resin composition constituting the surface layer. Lightfastness evaluation: Sample pieces were prepared from the films obtained in Examples 1 and 2 and Comparative Examples 1 to 7, the edges of these films were fixed with double-sided adhesive tape, and the samples were fixed with a sample made by Gas Test Instruments Co., Ltd. The film was placed in a shine carbon weatherometer, and ultraviolet light was irradiated from the surface layer side of the film. Bend the edge of the film that has been irradiated with ultraviolet rays,
The ultraviolet irradiation time required until cracks appeared was measured. The results are shown in Table 1 below.

【table】

[Table] Note that 300 hours of deterioration measured by a weatherometer corresponds to six months to nine months of deterioration when the film is stored outdoors. In addition, the components of the antioxidant used in the examples are as follows. (i) “Irganox 1076” manufactured by Ciba Geigy Octadecyl-3-(3,5-di-tert-butyl-4)
-Hydroxyphenyl)-propionate (ii) Adeka Argus'"Mark329" Mixture of tri(mononylphenyl) phosphite and tri(dinonylphenyl) phosphite (iii) Yoshitomi Pharmaceutical's "Yoshinotx BHT" 2,6-
Di-tert-butyl para-cresol.

Claims (1)

[Claims] 1 (A) Olefin resin 100 parts by weight (B) Calcium carbonate fine powder 3 to 300 parts by weight (C) Titanium oxide fine powder 1 to 60 parts by weight (D) Bis (2, 2, 6 ,6-tetramethyl-4-
(piperidyl) sebacate 0.05 to 5 parts by weight A resin composition characterized in that the above components (A) to (D) are blended in the above proportions.