JP2002337282A - Satin-like film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a satin-like film based on a polyolefinic resin being a substitute of a soft vinyl chloride resin, capable of being provided with a satin- like surface without applying processing by an embossing roll, a mat roll, sand blasting or the like and excellent in heat resistance, flexibility, perforation properties, blocking resistance, printability or the like. SOLUTION: The satin-like film is constituted by providing a surface layer on at least one surface of a core material layer based on a polyethylenic resin. The surface layer comprises a polyolefinic resin with a degree of crystallization of 40% or less based on a polypropylene resin and a polyolefinic elastomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satin film. More specifically, it has a polyolefin resin as a main component and has excellent flexibility, blocking resistance, and printability, and is suitable for use in advertisements, labels, stationery, desk mats, covers, packaging, adhesive tape substrates, etc. It is about a film.

[0002]

2. Description of the Related Art Soft vinyl chloride resins known as general-purpose resins are used in various applications because of their excellent flexibility, weather resistance, transparency and the like. However, soft vinyl chloride resin containing chlorine such as soft vinyl chloride resin,
It is said that during incineration, harmful substances such as hydrogen chloride gas and dioxin, which are highly toxic to humans, which cause acid rain may be generated, which is said to cause environmental pollution.
In addition, the plasticizer added to the soft vinyl chloride resin migrates to the film surface or a material that comes into contact with the plasticizer, thereby deteriorating the appearance or emitting odor. Furthermore, the influence of plasticizers on the human body has become a social problem, and in recent years, there has been a tendency to avoid using soft vinyl chloride resins.

As an alternative to the soft vinyl chloride resin, a polyolefin resin has been studied. For example, as a film having a matte surface, a surface layer made of a polypropylene resin and a base material made of a polyolefin thermoplastic elastomer are used. No. 10-2111676
JP-A-9-309187 discloses an automatic packaging film in which a matte roll is applied to the surface of a polyethylene laminated film using a mat roll.

[0004] In order to give the film an aesthetic or matte effect, as a method of forming a satin-finished surface, conventionally, the film surface is pressed against an embossing roll or a mat roll to form irregularities during film formation, or a sandblasting method is used. Although a method of providing unevenness is used, the cost is high because the process becomes complicated or a separate process is required to perform matting.

As a method of obtaining a matte film surface without performing the above-mentioned surface processing, for example, a method of forming a matte surface or an embossed surface using a polymer blend (Japanese Patent Laid-Open No. Hei 7-132961) Further, a method of biaxially stretching a laminate of a polyolefin-based resin blend to obtain a mat-like composite film (JP-A-10-86299) and the like have been proposed. However, when a film made of a resin blended with ordinary polypropylene and polyethylene is used, the haze is high due to incompatibility, and a matte film is formed.However, the surface becomes slightly rough, a beautiful appearance is not obtained, and printability is poor. Will be insufficient. In the method of stretching the laminate, a mat-like appearance is obtained, but the elastic modulus of the film tends to increase and the flexibility tends to be poor.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to replace a soft vinyl chloride resin, which is considered to have an adverse effect on the environment, with a polyolefin resin as a main component and processing embossing rolls, mat rolls, sand blasts and the like. The present invention provides a satin-finished film that can obtain a satin-finished surface without being subjected to heat treatment, and is excellent in heat resistance, flexibility, opening properties, blocking resistance, printability, and the like.

[0007]

Means for Solving the Problems As a result of diligent research for solving the above problems, a satin-finished film having the following constitution was found. (1) A surface layer is provided on at least one surface of a core material layer mainly composed of a polyethylene resin, and the surface layer has
A satin-like film composed of a polyolefin-based resin containing a polypropylene-based resin and a polyolefin-based elastomer as main components and having a crystallinity of 40% or less. (2) The film has a surface haze based on JIS K-7136 of 50% or more and JIS K-7113.
The matte-like film according to (1), having a tensile modulus of 200 MPa or less based on the following. (3) The polyethylene resin of the core material layer is at least one selected from low-density polyethylene, linear low-density polyethylene, and ethylene-vinyl acetate copolymer (1).
Or the satin-like film according to (2). (4) The surface of the film based on JIS K-6768,
The wetting index is 36 dyne / cm or more (1)-
The satin-like film according to any of (3).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The satin-like film of the present invention has a surface layer on at least one surface of a core layer mainly composed of a polyethylene resin, and this surface layer is made of a polypropylene resin and a polyolefin resin. It is a satin-like film made of a polyolefin-based resin containing an elastomer as a main component. Further, a surface layer may be formed on both surfaces of the core material layer. It is of course possible to use it.

The polyolefin-based resin used in the surface layer of the present invention is obtained by blending a polyolefin-based elastomer with a polypropylene-based resin, and includes a finely dispersed blend alloy, a reactor alloy and the like. Its crystallinity needs to be 40% or less, preferably in the range of 0 to 35%. If the degree of crystallinity exceeds 40%, the internal haze increases and the surface haze decreases, so that the matte feeling is lost and a matte surface cannot be obtained.
Further, printability and flexibility are reduced.

As the polypropylene resin in the surface layer, not only propylene homopolymer but also ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, Examples include α-olefins represented by octene, aromatic olefins represented by styrene, and copolymers of propylene with a monomer copolymerizable with propylene such as dienes represented by butadiene. The components and amounts of the copolymers are not limited.

The polyolefin elastomer in the surface layer is a copolymer of at least two kinds of α-olefins, for example, an ethylene-propylene copolymer, an ethylene-1-butene copolymer, and an ethylene-olefin copolymer. 1-pentene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-1-hexene copolymer, ethylene-1-heptene copolymer, ethylene-1-octene copolymer, ethylene-propylene -Butene copolymer and the like, but are not limited thereto.

As described above, as the polyolefin resin for the surface layer of the present invention, a blend of a polypropylene resin and a polyolefin elastomer is used. In particular, a resin obtained by a method such as a blend alloy or a reactor alloy is used. preferable. The polyolefin resin obtained by these blending methods has a structure in which polyolefin elastomer islands are very finely dispersed in the sea of polypropylene resin, and when formed into a film, has a beautiful matte Appearance is obtained and it becomes satin-like.

Examples of the blend alloy include "CAP" manufactured by Ube Industries, Ltd., and examples of the reactor alloy include "FPO" manufactured by Lexen, "Cataroy" manufactured by Montel SDC Sunrise, and the like. . However, it is not limited to these.

The surface layer in the present invention may have an antioxidant such as phenylenediamine and hindered phenol, an antistatic agent such as glycerin monoester and ethoxylated amine, and an ultraviolet ray such as benzotriazole as long as no practical problems occur. An absorbent or the like may be added.

[0015] The polyolefin resin in the present invention relates to the anti-blocking property at room temperature and, for example, 50%.
It is good even at a high temperature and high humidity of 90 ° C. and 90% RH. Further, in order to improve blocking resistance and change the feeling of touch, an inorganic pigment such as silica, talc, calcium carbonate, and diatomaceous earth, and an organic pigment such as polymethyl methacrylate may be added. Further, inorganic pigments and organic pigments added for these purposes are not limited to these.

The surface haze of the satin-like film of the present invention is 5
0% or more is preferable, and the upper limit is 100%. When the surface haze is less than 50%, the appearance is not matte, and the satin-like appearance tends to be deteriorated. Further, the surface has insufficient unevenness due to insufficient unevenness, and the touch feeling is also poor. May be unsatisfactory. The surface haze in the present invention is a value obtained by subtracting the internal haze from the total haze, and is based on JIS K-7136.

The tensile modulus of the satin-like film of the present invention is:
200 MPa or less is preferable, 10-200 MPa is more preferable, and 20-200 MPa is especially preferable. When the tensile modulus exceeds 200 MPa, the rigidity increases, and the flexibility becomes insufficient and the followability of the curved surface tends to be poor in applications such as advertisements, labels, stationery, desk mats, covers, packaging, and adhesive tape base materials. There is. On the other hand, if the tensile modulus is excessively low, poor handling due to lack of strain on the film may become a problem. The tensile modulus of the present invention is based on JIS K-7113.

The core layer in the present invention is mainly composed of a polyethylene resin and is intended to impart flexibility to the laminated film, and is advantageous in terms of cost. Examples of the polyethylene resin include not only homopolymers of ethylene, but also α-olefins such as propylene, butene, and pentene, and copolymers of ethylene and a monomer copolymerizable with ethylene such as vinyl acetate. . The copolymer of ethylene and α-olefin includes linear low-density polyethylene.

As the polyethylene resin for the core material layer, preferably low-density polyethylene, linear low-density polyethylene,
And at least one of ethylene-vinyl acetate copolymer and the like. The density of low-density polyethylene, or linear low density polyethylene is preferably from 0.925 g / cm ³ or less, more preferably 0.922 g / cm ³ or less,
0.920 g / cm ³ or less is particularly preferred. Ethylene-
As the vinyl acetate copolymer, those used for film applications are excellent in flexibility and extremely suitable as a core material layer, and have a melt flow rate (MFR) of 0.1 to 4.
About 0 g / 10 min is preferable.

In the core material layer of the present invention, an antioxidant such as phenylenediamine and hindered phenol, an antistatic agent such as glycerin monoester and ethoxylated amine, and an ultraviolet ray such as benzotriazole are used unless a practical problem occurs. An additive such as an absorbent may be added.

The total thickness of the satin-like film of the present invention is generally about 10 to 1000 μm, preferably 15 to 1000 μm.
It is 900 μm, more preferably 20 to 800 μm.
For example, in the case of a three-layer configuration of a surface layer / core layer / surface layer, the thickness ratio of each layer is preferably 5/90/5 to 45 /
10/45, more preferably 10/80 /
It is in the range of 10-40 / 20/40. The layer configuration is not limited to the three-layer configuration, but may be a configuration of four or more layers, or two or more core material layers. For example, in order to prevent curling of the laminated film, the thickness of each layer is appropriately distributed in consideration of the contraction force of each layer such as the surface layer and the core material layer. More preferably, in both surface layers of the core material layer, the same type of resin is used among the polyolefin-based resins, and curl control becomes easy.

The satin-finished film of the present invention is formed by a known molding method such as, for example, a T-die method, an air-cooled inflation method, or a water-cooled inflation method, but is not limited thereto. The method of lamination in the case of a multilayer film is not particularly limited, and is laminated by a known method such as a dry lamination method, a wet lamination method, a melt extrusion lamination method, and a melt coextrusion method. , A T-die method, an air-cooled inflation method, a water-cooled inflation method, or the like.

The satin-finished film of the present invention may be subjected to corona treatment, plasma treatment,
It is preferable to perform a treatment such as a flame treatment. At this time, the wetting index of the surface of the film is preferably 36 dyne /
cm or more. In the present invention, the wetting index is a value measured according to JIS K-6768.

[0024]

The present invention will be described in more detail with reference to the following Examples, which, of course, are not intended to limit the scope of the present invention.

Example 1 As the resin for the core material layer, the density was 0.912 g / cm ³ ,
Linear low density polyethylene (LLDPE) having an FR of 2.0 g / 10 min (trade name: FV203, manufactured by Sumitomo Chemical Co., Ltd.)
And a density of 0.89 g /
cm ³ , melt flow rate (MFR) 2.5 g / 1
For 0 min, a polyolefin resin having a crystallinity of 24.3% (trade name: KS-221P, manufactured by Montell S.K. Sunrise Co., Ltd., a polypropylene resin blended with an ethylene-propylene copolymer) was used.
The film was formed by air-cooled multilayer inflation using a circular die, the temperature of the die was set to 220 ° C., and the surface layers were formed on both sides of the core material layer so that the total thickness of the film became 100 μm. The thickness of each layer is 15
μm, and the core material layer was 70 μm. Further, the surface of this film was subjected to corona treatment so as to have a wetting index of 40 dyne / cm to obtain a satin-finished three-layer film.

Example 2 As the resin for the core material layer, the density was 0.912 g / cm ³ ,
Linear low density polyethylene (LLDPE) having an FR of 2.0 g / 10 min (trade name: FV203, manufactured by Sumitomo Chemical Co., Ltd.)
And a density of 0.89 g /
cm ³ , MFR 0.8 g / 10 min, crystallinity 1
7.2% polyolefin resin (trade name: KS-02)
1P, manufactured by Montell S.K. Sunrise Co., Ltd., obtained by blending an ethylene-propylene copolymer with a polypropylene resin). The film was formed by an air-cooled multilayer inflation method using a circular die, the temperature of the die was set to 220 ° C, and the total thickness of the film was 150
Surface layers were formed on both sides of the core material layer so as to have a thickness of μm.
The thickness of each layer is 25 μm for the surface layer and 100 μm for the core material layer.
μm. In addition, a wetting index of 4
Corona treatment was performed so as to be 0 dyne / cm to obtain a satin-finished three-layer film.

Example 3 A resin having a density of 0.912 g / cm ³ and M
Linear low density polyethylene (LLDPE) having an FR of 2.0 g / 10 min (trade name: FV203, manufactured by Sumitomo Chemical Co., Ltd.)
And a density of 0.89 g as a resin for the surface layer.
/ Cm ³ , MFR 2.5 g / 10 min, crystallinity 24.3% polyolefin resin (trade name: KS-2)
21P, manufactured by Montell SDC Sunrise Co., Ltd.)
Was used. The film was formed by a multilayer extrusion casting method using a T-die, with the temperature of the die set at 220 ° C. and the surface layers formed on both sides of the core material layer so that the total thickness of the film was 800 μm. The thickness of each layer is 12
0 μm and the core material layer was 560 μm. Further, the surface of this film was subjected to corona treatment so as to have a wetting index of 40 dyne / cm to obtain a satin-finished three-layer film.

Comparative Example 1 As the resin for the core material layer, the density was 0.912 g / cm ³ , M
Linear low density polyethylene (LLDPE) having an FR of 2.0 g / 10 min (trade name: FV203, manufactured by Sumitomo Chemical Co., Ltd.)
And a polyolefin resin for the surface layer having a density of 0.90 g / cm ³ and an MFR of 2.5 g / 10 mi.
n, polypropylene having a crystallinity of 48.9% (trade name:
RF1342, manufactured by Grand Polymer Co., Ltd.). The film was formed by air-cooled multilayer inflation using a circular die, the temperature of the die was set to 220 ° C., and the surface layers were formed on both sides of the core material layer so that the total thickness of the film became 100 μm. The thickness of each layer is 15 μm for each surface layer.
m, the core material layer was 70 μm. Further, the surface of this film was subjected to a corona treatment so that the wetting index became 40 dyne / cm, to obtain a three-layer film.

Comparative Example 2 As the resin for the core material layer, the density was 0.90 g / cm ³ , MF
R is 2.0 g / 10 min polypropylene (trade name:
RF1342, manufactured by Grand Polymer Co., Ltd.), and as a resin for the surface layer, a density of 0.89 g / cm ³ , MFR
Was used, and a polyolefin-based resin having a crystallinity of 24.3% (trade name: KS-221P, manufactured by Montell S.K. Sunrise Co., Ltd.) was used. The film was formed by air-cooled multilayer inflation using a circular die, the temperature of the die was set to 220 ° C., and the surface layers were formed on both sides of the core material layer so that the total thickness of the film became 100 μm. The thickness of each layer is 15 μm for each surface layer.
m, the core material layer was 70 μm. Further, the surface of this film was subjected to a corona treatment so that the wetting index became 40 dyne / cm, to obtain a three-layer film.

Evaluation Test The resin used in each of the above Examples and Comparative Examples, and the physical properties or quality of the obtained films were evaluated according to the following criteria. The results are shown in Table 1.

(1) Crystallinity The temperature was raised from 40 ° C. to 200 ° C. at a rate of 10 ° C./min by DSC (differential scanning calorimetry) to determine the heat of fusion. The heat of fusion of the polypropylene complete crystal was 164 J / g, and the value obtained by dividing the obtained heat of fusion by the heat of fusion of the complete crystal was defined as the crystallinity.

(2) Surface haze According to JIS K-7136, all hazes were measured,
The internal haze was measured by coating commercially available liquid paraffin on the film surface. The difference between the total haze and the internal haze was defined as the surface haze.

(3) Evaluation of mattability The surface of the film was visually evaluated as good (○) when the film had matteness, and poor (x) when the film was not matte.

(4) Tensile Modulus The obtained film was measured according to JIS K-7113.

(5) Blocking Resistance The obtained film is cut into a square of 50 mm × 50 mm, and two of them are superimposed to obtain a sample. Prepare five sets of samples. This sample is sandwiched between 60 mm × 60 mm holding plates, and a 2 kg weight is placed thereon. (1) The temperature is 40 ± 1 ° C.
It is left for one day under the condition of 70 ± 2% RH in humidity and (2) three days under the condition of 50 ± 1 ° C. and no humidity limitation. When the sample was peeled off by hand and peeled off, it was evaluated as “good”, and when it was not peeled off, it was evaluated as “bad”.

(6) Printability Using an RI-1 print tester manufactured by Ishikawajima Sangyo Co., Ltd.
The ultraviolet curable ink was solid-printed so that the optical density was in the range of 1.8 ± 0.2, and the presence or absence of unevenness was visually evaluated after curing treatment by irradiation with ultraviolet light. A sample without unevenness was evaluated as “good”, and a sample with unevenness was evaluated as “bad”. afterwards,
The ink adhesion was evaluated by 180 ° peeling with Nichiban cellotape. A sample without any ink peeling was rated "good", and a sample with ink peeling was rated "bad".

(7) Evaluation of curl Using an A4 size film sample, the film was placed on a horizontal surface such that the convex curl side of the film was in contact with the flat surface on which the film was placed, and the state of curl was visually observed. . As a result, regarding the films obtained in each of the examples and the comparative examples, the maximum height of each of the four corners was 10 mm or less, and almost no curling was observed.

[0038]

[Table 1]

[0039]

According to the present invention, a matte-like surface can be easily formed without using a polyolefin resin as a substitute for a soft vinyl chloride resin, and without processing such as embossing rolls, mat rolls, and sandblasting. It is possible to obtain a satin-like film having excellent anti-blocking properties, printability and the like and having almost no curl, which is extremely useful in industry.

Continued on the front page F-term (reference) 4F100 AK03A AK03C AK06B AK07A AK07C AK63B AK64 AK68B AL05A AL05C AL09A AL09C BA03 BA06 BA10A BA10C EH20 EJ55 GB15 GB90 JA11A JA11C JK17 JL00 YY00A YBWB BBX4JB14 BBX4

Claims (4)

[Claims] 1. A core layer comprising a polyethylene resin as a main component and a surface layer provided on at least one surface of the core material layer, wherein the surface layer comprises a polypropylene resin and a polyolefin elastomer as main components, and has a crystal structure. A matte-like film comprising a polyolefin resin having a degree of conversion of 40% or less. 2. The film according to JIS K-7136.
Surface haze based on JIS is 50% or more and JIS
The satin-finished film according to claim 1, having a tensile modulus of 200 MPa or less based on K-7113. 3. The satin-like film according to claim 1, wherein the polyethylene resin of the core material layer is at least one selected from low-density polyethylene, linear low-density polyethylene, and ethylene-vinyl acetate copolymer. . 4. JIS K-67 on the surface of the film
The satin-finished film according to any one of claims 1 to 3, wherein a wetting index based on 68 is 36 dyne / cm or more.