JPH07330923A - Flexible olefin film - Google Patents

Abstract

PURPOSE:To prepare a film which substantially contains no plasticizer, is excellent in flexibility, extensibility, and drape, and is suitable as a substrate of a first-aid adhesive plaster. CONSTITUTION:This flexible olefin film is made from a polypropylene resin having one or more melting peaks measured by differential scanning calorimetry in the temp. range of 130-170 deg.C and a total amt. of heat of melting at these melting peaks of 5-45mJ/mg and has a thickness of 15-300mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft film made of a polypropylene resin, and more specifically, a soft olefin film made of a polypropylene resin having a specific melting peak and having a heat of fusion within a specific range. Regarding The soft olefin film of the present invention is suitably used, for example, as a base film for a first aid bandage.

[0002]

2. Description of the Related Art Generally, a plaster, particularly an emergency plaster, is manufactured through the following steps. First, a soft film is prepared, a pressure sensitive adhesive is applied to the surface of the soft film, gauze or the like is further mounted on the pressure sensitive adhesive, and release paper is laminated to obtain a layered product. Next, the layered product thus obtained is punched out into a predetermined size, and then the wrapping paper is placed on the front and back surfaces of the punched layered product, and further cut into a predetermined size to obtain an emergency bandage.

As the soft film used in the above-mentioned first aid bandage, considering flexibility, elasticity and texture,
A material containing plasticized polyvinyl chloride (hereinafter abbreviated as plasticized PVC) prepared by a calendar method or a sol cast method as a main component has been widely used.

However, plasticized PVC films contain large amounts of plasticizer. Therefore, the plasticizer migrates from the film to the pressure-sensitive adhesive side, whereby the pressure-sensitive adhesive force of the pressure-sensitive adhesive is reduced, or the adhesive force between the film and the pressure-sensitive adhesive is reduced, and as a result, the adhesive bandage is easily peeled off. There was a problem of becoming. Further, in recent years, the pros and cons of using plasticized PVC, which is a polymer containing chlorine, has been discussed in various fields due to environmental problems.

Therefore, as a material replacing plasticized PVC, a polyolefin resin having flexibility and high elasticity is being actively developed. Examples of such polyolefin resins include films using polyethylene, ethylene-vinyl acetate copolymer, polybutadiene, ethylene-propylene copolymer, and the like, and as a film for a first-aid bandage, Japanese Patent Publication No. 57-1
1342 discloses a film obtained by stretching a polyolefin composition comprising at least one of ethylene-α-olefin copolymer, LDPE (low density polyethylene) and PP (polypropylene) by 1.5 to 3.5 times. JP-A-62-82967 discloses a film comprising a hydrocarbon-based elastomer such as ethylene-propylene rubber or ethylene-propylene-diene terpolymer, and a polyolefin blend such as ethylene-vinyl acetate copolymer. Is disclosed.

However, the film made of the polyolefin resin as described above has a problem that the stretchability and stress relaxation property at the time of application are not sufficient, which are required for the first aid bandage. That is, because the stretchability of the film is not sufficient, it may be loosened immediately after application, or because the stress relaxation property of the film is not sufficient, when the film is attached to the affected area, the affected area may be pressed or, after being applied, immediately peeled off. It was often not suitable for actual use.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the drawbacks of conventional polyolefin resins when used in a first aid bandage. Contains virtually no agent, has excellent flexibility and elasticity, and stress relaxation during stretching occurs quickly. For example, when used in an emergency bandage, it is possible to reduce pressure on the affected area and it has an excellent texture. , An object is to provide a soft olefin film.

[0008]

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that a specific melting peak obtained by a multi-stage polymerization method and a specific copolymer having a specific heat of fusion are obtained. It was found that the above object can be achieved by using the combined product, and the present invention has been completed based on this finding.

The soft olefin film of the present invention has a DS
The melting peak measured by C (differential scanning calorimeter) is 13
At least one is present between 0 ° C. and 170 ° C., and the total heat of fusion at the peak is 5 to 45 mJ /
The film is made of a polypropylene resin characterized by being mg, and has a thickness in the range of 15 to 300 μm.

The polypropylene resin forming the film of the present invention preferably has at least one melting peak in the range of 130 ° C. to 170 ° C., as measured by the DSC described below. If there is no melting peak within this range, the heat resistance, strength and stretchability of the film will decrease.

The total amount of heat of fusion at that time is 5 to 4
It is preferably in the range of 5 mJ / mg, more preferably 7 to 35 mJ / mg. Heat of fusion is 5 mJ
If less than / mg, heat resistance and strength will decrease, and
When the amount exceeds J / mg, the amount of polypropylene crystals increases, which may cause problems in flexibility of the film and wearing feeling on a human body (finger, etc.) when used as a bandage.

The polypropylene resin used in the present invention is obtained by multistage polymerization of two or more stages. First, in the first stage, it is preferable to polymerize a propylene homopolymer, a propylene-ethylene copolymer, or a propylene-α-olefin copolymer in an amount of 5 to 35% by weight, more preferably 5 to 30% by weight. . Next, in the second and subsequent stages, the ethylene-propylene copolymer elastomer is charged to 65 to
The polymerization is preferably 95% by weight, more preferably 70 to 95% by weight.

If the amount of propylene homopolymer, propylene-ethylene copolymer or propylene-α-olefin copolymer polymerized in the first stage is less than 5% by weight, the resulting soft film becomes very flexible. , The film strength is reduced. Further, when it exceeds 35% by weight,
This causes a problem in the flexibility of the film.

Further, if the ethylene-propylene copolymer elastomer polymerized in the second and subsequent stages is less than 65% by weight, the flexibility of the film is lowered, and if it is more than 95% by weight, the film strength is reduced.

In the above propylene-ethylene copolymer or propylene-α-olefin copolymer, the amount of ethylene or α-olefin is preferably 10% by weight or less with respect to propylene.

The ethylene content of the ethylene-propylene copolymer elastomer is preferably in the range of 15 to 65% by weight, more preferably 15 to 6%.
It is 0% by weight. Such an ethylene-propylene copolymer elastomer is generally called an ethylene-propylene rubber (rubber). In the present invention, this ethylene-
The propylene rubber is characterized in that it is polymerized in the second and subsequent stages in the multi-stage polymerization, and as a result, the propylene homopolymer or propylene-ethylene copolymer or propylene-α-olefin polymerized in the first stage is obtained. Since the copolymer and the ethylene-propylene rubber are mixed at the molecular structure level (nano order), a very uniform and flexible olefin film is obtained.

The α-olefin in the various copolymers of the present invention has 4 or more carbon atoms, for example, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-butene.
Examples include octene.

The thickness of the film of the present invention is 15 to 300.
μm, preferably 30 to 200 μm, and more preferably 50 to 90 μm. If it is thinner than 15 μm,
Problems such as cutting at the time of manufacturing or mounting, 300 μm
If it exceeds, it is inflexible and becomes difficult to stick when wrapped around a thin object such as a finger.

The polypropylene resin forming the film of the present invention is specifically produced by, for example, the following multistage polymerization method. First, as the first step, in the presence of a titanium compound catalyst and an aluminum compound catalyst,
Polymerization is performed using a propylene monomer and, if necessary, an α-olefin monomer other than propylene to obtain a first propylene-based polyolefin. The polyolefin can be a propylene homopolymer, a propylene-ethylene copolymer, a propylene-α-olefin copolymer, and the like. In the second step, the titanium-containing propylene-based polyolefin and the olefin monomer (ethylene, propylene) are copolymerized in the presence of the above-mentioned compound in the presence of the titanium compound catalyst and the aluminum compound catalyst to obtain a second polyolefin. To get Similarly, a multi-step copolymerization reaction can be performed depending on the purpose.

Several methods have already been proposed as methods for producing these polypropylene resins. For example, there is a method described in Japanese Patent Laid-Open No. 4-224809. In this method, as a titanium compound, for example, titanium trichloride and magnesium chloride are co-ground, and n-butyl orthotitanate, 2-ethyl-1-hexanol, ethyl p-toluate, silicon tetrachloride, diisobutyl phthalate, etc. are used. A spherical Ti catalyst having an average particle diameter of 15 μm prepared by treatment is used, an alkylaluminum such as triethylaluminum is used as an aluminum compound, and a silicon compound, particularly diphenyldimethoxysilane, is added as an electron donor in the polymerization tank. Furthermore, ethyl iodide is also added. The most important feature of this production method is that the polymerization is not completed once but is a multi-stage polymerization of two or more stages. That is, it is possible to form multiple types of polymers in succession during the polymerization, and this method produces a blend type copolymer at a molecular level which is completely different from a usual polymer blend.

Further, in a resin such as a conventional block polypropylene copolymer, a block portion copolymerized with propylene, that is, propylene-ethylene, propylene-
The content of the rubber component composed of the α-olefin copolymer is
Due to the manufacturing process, the limit was about 50% by weight of the original propylene. Therefore, it has been extremely difficult to realize flexibility such as plasticized PVC with a polypropylene resin.

However, if the above-mentioned polymer blend is used, the rubber component comprising the above-mentioned copolymerized portion is added in an amount of about 80 to 95.
It is possible to contain up to wt%, plasticized PVC
A resin having the same physical properties as described above can be obtained, and it becomes possible to prepare a blend composition in which the resin viscosity is not possible by a usual blending method using an extruder or the like. In addition to the method described above, the method for producing such a resin composition is described in JP-A-4-96912 and 4-9.
No. 6907, No. 3-174410, No. 2-170803.
No. 2-170802, JP-A-61-42553,
It is also described in JP-A-3-205439. Further, in JP-A-3-97747, a titanium compound in which an adduct of magnesium chloride and alcohol is first formed and then the adduct is treated with titanium tetrachloride and an electron donor is also used. . As the polypropylene resin in the present invention, any of these methods can be used without any trouble. The resin obtained by the above manufacturing method is "PE of Tokuyama Soda Co., Ltd."
“R (trade name)” and “Cataloy (trade name)” of Highmont Co. are exemplified.

The polypropylene film thus obtained can be formed into a film having a predetermined thickness by a usual method such as a T-die extruder or an inflation method.
Since it does not contain a plasticizer, it is flexible and has elasticity, and the stress relaxation at the time of extension is fast, so that when used as a constituent material of a bandage, it does not press the affected area, and a first-aid bandage with a good texture can be obtained.

The reason for producing such a result is not clear, but is estimated as follows. It is considered that the polypropylene-based resin used in the present invention is such that a large amount of an amorphous polymer represented by ethylene-propylene copolymer or the like is introduced into the polypropylene resin during the polymerization, and these polymers are alloyed. . It seems that the production of this type of resin is made possible by the use of titanium catalysts, which are very active and have a long life. Due to such polymerization, there are several copolymers having different molecular structures in the polymer, and it is considered that the morphology characteristic of the alloy between the ordinary resin part such as polypropylene and these copolymer parts is expressed. To be As a result, it is considered that the soft olefin film of the present invention exhibits physical properties very close to those of plasticized PVC, even though it is a material having no crosslinking in the resin.

The soft olefin film of the present invention may be a colorless and transparent film, a colored and transparent film, or a colored and non-transparent film. By using the soft olefin film of the present invention as a base material, for example, a first aid bandage can be obtained. An example of manufacturing the first aid bandage will be described below.

First, after subjecting one side of the soft olefin film of the present invention to corona treatment or anchor coating, if necessary, a pressure-sensitive adhesive layer is provided, gauze or the like is laminated thereon, and release paper is further laminated. It is obtained by punching this into a predetermined size, stacking individual wrapping paper on the front and back surfaces, and further cutting it into a predetermined size. When the corona treatment is performed, it is preferable that the surface tension of the film is about 38 dyn / cm or more.

The above-mentioned pressure-sensitive adhesive layer may be provided on the entire surface of the substrate film, or it may be a fine line, a lattice, a dot, or a surface having a large number of small circles on which no pressure-sensitive adhesive is applied. It may be freely set depending on the purpose such as the shape.

The pressure-sensitive adhesive layer is not particularly limited, and examples thereof include natural rubber type, synthetic rubber type, acrylic type,
Various adhesives such as urethane type, vinyl ether type and silicone type are preferably used, and the form thereof may be any of solvent type, emulsion type, hot melt type and the like.

The method of applying the above-mentioned pressure-sensitive adhesive to the substrate film is not particularly limited, and the pressure-sensitive adhesive may be directly applied to the film surface, or such as release paper or release film. A method may be adopted in which a pressure-sensitive adhesive is applied to the release-treated surface of the separator and then the pressure-sensitive adhesive is transferred to the film side by superimposing the pressure-sensitive adhesive on the base film.

In addition, the soft olefin film contains
Various types of printing can be performed in any shape and size depending on the purpose. For example, shapes such as a mesh shape, a dot shape, and an infant character can be printed.

The soft olefin film referred to in the present invention includes an ethylene-propylene rubber, an ethylene-butene copolymer, a propylene homopolymer, a propylene-ethylene copolymer, and a propylene-polymer film to the extent that the physical properties of the film are not impaired during the molding. An α-olefin copolymer, polyethylene using a metallocene catalyst, especially an ethylene-α-olefin copolymer may be added.

To the soft olefin film of the present invention, stabilizers such as antioxidants and ultraviolet absorbers, fillers such as precipitated barium sulfate, talc, calcium carbonate, mica and titanium oxide, colorants and the like can be added.

[0033]

The soft olefin film of the present invention is obtained by the above multistage polymerization method, and is composed of a specific copolymer having a specific melting peak and a specific heat of fusion.
Furthermore, since the film is formed so as to have a thickness within the above-mentioned specific range, the stretchability and self-healing property of the film are excellent, as will be apparent from the examples described later.

[0034]

EXAMPLES The present invention will be specifically described below based on examples, but the present invention is not limited thereto.

In the following examples, the melting peak of polypropylene resin, the amount of heat of fusion, the amount of each copolymer component and the ethylene content, the tensile strength of the film, the elongation recovery rate, the stress relaxation, and the human body (a finger when processed into a first-aid bandage) The wearing feeling in () was tested by the method described below.

1. Melting peak of polypropylene resin,
And heat of fusion About 10 mg of the polypropylene resin of the present invention was placed in a platinum pan, and a differential scanning calorimeter (DSC) <manufactured by Seiko Instruments Inc .:
SSC-5000 type>. In the measurement, the sample was melted once, cooled to −50 ° C. at a rate of 5 ° C./min, and then heated at a rate of 5 ° C./min for measurement.

2. The amount of each copolymer and the ethylene content were measured by the cross fractionation method described below. The polypropylene resin is first dissolved in o-dichlorobenzene at a temperature at which the polypropylene resin is completely dissolved, and 0.5 ml of a sample sample solution (0.4 wt% concentration) at 140 ° C. is sampled and set on the TREF column. did. Next, a certain condition (1
(° C / min), the temperature was lowered to 0 ° C, and the temperature was maintained for 30 minutes. Next, elution is performed sequentially from the low temperature side at a flow rate of 1.0 ml, and SEC
(SEC = Size Exclusion Chromatograph) Column (1
40 ° C.), and the amount of each copolymer was calculated in the SEC section for each eluted component. The column used is GPC AD-
806MS (8 mm diameter x 250 mm length x 3 series: Showa Denko KK). This method is called temperature rising elution fractionation.

Further, the low temperature elution component was measured by ¹ H, ¹³ C-NMR, and the ethylene content was determined from the integrated intensity ratio of the methyl group and the methylene group.

3. Tensile strength A tensile tester was used to measure the tensile strength at a sample width of 20 mm, an initial sample length (grip interval) of 100 mm, a tensile speed of 200 mm / min, and an elongation of 5% and 10%.

4. Elongation recovery rate Marked lines at intervals of 50 mm are written on strip-shaped samples with a width of 20 mm, and an initial sample length (grasping interval) of 100 is obtained by a tensile tester.
mm, pulling rate at 200 mm / min to 50% elongation, the sample is immediately removed, and after 5 minutes, the marked line interval is measured to calculate the permanent strain (elongation). When this permanent set is Y%, the elongation recovery rate (%) is obtained by the following equation.

[0041]

[Equation 1]

5. Stress relaxation Using a tensile tester, a sample width of 20 mm, an initial sample length (grasping interval) of 100 mm, and a tensile speed of 200 mm / min were pulled to an elongation of 10%, and then the tensile strength was maintained for 5 seconds. And after 1 minute, the rate of residual stress was calculated by the following formula.

[0043]

[Equation 2]

6. Feeling of wearing on human body (finger) The first-aid bandage was wrapped around the second joint of the index finger, and the feeling (compression) when the finger was bent or extended was evaluated.

Example 1 The melting peak measured by DSC was 165.0 ° C., the heat of fusion was 26.3 mJ / mg, each component was 15% by weight of propylene-ethylene copolymer, and the ethylene-propylene copolymer was 15% by weight. A polypropylene resin containing 85% by weight of polymer (ethylene content 20% by weight) was used to form a film as follows.

That is, the polypropylene resin is added to T
The die was extruded at a mold temperature of about 240 ° C. to form a film substrate having a thickness of 70 μm. The formed film surface is subjected to corona discharge treatment, rolled up, and vertically (M
The tensile strength, elongation recovery rate, and stress relaxation property in the D) direction and the transverse (TD) direction were measured. The results are shown in Table 1 below.

Then, a rubber adhesive solution (35% toluene solution of natural rubber, polyterpene resin, polybutene, and antioxidant) was applied onto the release paper using a coating and drying winder to give a thickness after drying of 40 μm. Was coated and dried to form a pressure-sensitive adhesive layer. Next, the pressure-sensitive adhesive layer surface was attached to the corona-treated surface of the above-mentioned polyolefin resin film, laminated, and wound into a roll by a winder. Using a slitter, roll this roll of emergency tape tape for 78m
It was cut into m widths and rewound into long lengths (20 m). The obtained tape tape for adhesive plasters having a width of 78 mm was processed by the following processing device for emergency adhesive plasters to obtain an emergency adhesive plaster.

This processing device is provided with a supply device of auxiliary materials for a first-aid bandage (gauze, release paper for replacement, individual wrapping, etc.) of a predetermined width, and the above-mentioned raw tape for a first-aid bandage applied to this device. When is fed, the release paper is peeled off, and the soft film layer and the pressure-sensitive adhesive layer are subjected to fine perforation processing. Next, the thickness of 1m on the upper surface of the adhesive layer
Gauze of m, width 17 mm × length 25 mm is attached, and the release paper for replacement is applied from above the gauze and the adhesive layer. The obtained laminate is given a predetermined size (width 20 mm x length 7
A first-aid adhesive plaster was obtained by punching out into a 5 mm, arcuate shape with a radius of 12 mm at both ends, packaging with an individual wrapping agent, and cutting. The feeling of wearing on the human body was evaluated using the obtained first aid bandage. The results are shown in Table 1 below.

Examples 2 and 3 A polypropylene resin having the melting peaks and heats of fusion shown in Table 1 and respective copolymerization components was formed into a film by the same method as in Example 1 and various evaluations were carried out.

Example 4 A polypropylene resin having a melting peak, a heat of fusion and a copolymerization component shown in Table 1 was used, and ethylene-propylene rubber (manufactured by Japan Synthetic Rubber Co., Ltd .: EP941P) was added to the polypropylene resin.
0% by weight was added, a film was formed in the same manner as in Example 1, and various evaluations were performed.

Example 5 A resin having the same thickness as that used in Example 1 was used as an intermediate layer, and the resin used in Example 2 was laminated on both sides thereof to form a film having a thickness of 65 μm. In the production of this film, the resin was extruded with an extruder having a diameter of 50 mm for both surface layers and a diameter of 65 mm for the central layer. The extrusion temperature was 230 ° C and the die temperature was 230 ° C. The apparatus used was a three-layer extrusion apparatus having a feed block, a mold, and three extruders. The thickness ratio of each layer is 1/10/1. Various evaluations were performed on the obtained film in the same manner as in Example 1. The results are shown in Table 1.

Comparative Examples 1 to 3 Using the resins having the characteristics shown in Table 2, films were formed in the same manner as in Example 1 to form films having a thickness of 70 μm, and various evaluations were carried out. The results are shown in Table 2.

[0053]

[Table 1]

[0054]

[Table 2]

[0055]

INDUSTRIAL APPLICABILITY As described above, the soft olefin film of the present invention is obtained by a multi-stage polymerization method, is composed of a polypropylene resin film having the above-mentioned specific melting peak and specific heat of fusion, and has a thickness of Since it is within the above-mentioned specific range, it exhibits excellent flexibility, elasticity, and texture when applied to the skin as an emergency bandage, which is not inferior to the conventional plasticized PVC film. Therefore, when the first-aid bandage is constructed using the soft olefin film according to the present invention, it is excellent in flexibility,
It is possible to obtain a first-aid bandage that has a low possibility of pressing the affected area and is excellent in texture, and, unlike PVC, it does not contain chlorine, so it is also excellent in safety and environmental pollution. Is unlikely to occur.

Claims (3)

[Claims] 1. At least one melting peak measured by a differential scanning calorimeter is present between 130 ° C. and 170 ° C., and the total calorific value of melting at the peak is 5-4.
A soft olefin film, which is made of a polypropylene-based resin of 5 mJ / mg and has a thickness of 15 to 300 μm. 2. In the first stage, at least one selected from the group consisting of propylene homopolymer, ethylene-propylene copolymer and propylene-α-olefin copolymer is polymerized by 5 to 35% by weight, Ethylene after the second stage
A soft olefin film comprising the polypropylene resin according to claim 1, which is obtained by multistage polymerization in which 65 to 95% by weight of a propylene copolymer elastomer is polymerized. 3. The soft olefin film according to claim 2, wherein the ethylene-propylene copolymer elastomer contains ethylene in an ethylene content range of 15 to 65% by weight.