JPH11157022A - Antibacterial polypropylene-based composite film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antibacterial polypropylene-based composite film, which has both antistatic properties and anti-fogging properties in combination, and is effective to a plurality of kinds of fungi. SOLUTION: This composite film is produced by laminating a surface layer made of a polypropylene-based resin containing 0.05-5 wt.% of antibacterial particles onto at least one side of a base layer consisting of biaxially stretched film of a resin mainly made of a polypropylene. The antibacterial particle includes antibacterial metal or metal ions. Concretely, the composite film includes 0.05-5 wt.% of a nonionic surface active agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene composite film having antibacterial properties. More specifically, the present invention relates to an antibacterial polypropylene-based composite film having both antistatic properties and antifogging properties.

[0002]

2. Description of the Related Art Polyolefins are generally considered to be materials having excellent resistance to microorganisms such as bacteria and molds, and are widely used as packaging films in the field of foods and the like. I have. However, with the recent public awareness of safety,
In the field of soft packaging such as household goods and medical goods, a biaxially stretched film with further improved antibacterial properties has been desired.

In order to impart antibacterial properties to a film, an antibacterial agent is generally blended. As an antibacterial agent in this case, an inorganic antibacterial agent is superior to an organic antibacterial agent in terms of heat resistance, durability, antibacterial spectrum width, etc., and also from the viewpoint of sanitary safety. Are suitable. As an example of a film having antibacterial properties, JP-A-2-247239 discloses a zeolite holding one or more metals selected from a metal group consisting of silver, copper, zinc and tin in an ionic state with polyolefin. A resin having a layer obtained by stretching in a -axial direction or a biaxial direction from the resin composition is used as a surface layer.

[0004]

By the way, it can be considered that the antibacterial effect obtained by blending the inorganic antibacterial agent depends on the amount of the antibacterial agent exposed on the film surface. Therefore, when antibacterial particles containing an inorganic antibacterial agent are kneaded into the entire layer of the film, the ratio of burying the antibacterial particles in the film increases. It was necessary to mix a large amount. However, increasing the amount of the antibacterial particles is disadvantageous in terms of cost and mechanical strength of the film, and also has the problem of degrading transparency.

When the antibacterial particles are compounded only in the surface layer of the composite film, the ratio of the antibacterial particles can be efficiently increased on the surface of the film which has the greatest effect on the antibacterial effect. The amount is small and effective. However, even in that case, the inorganic antibacterial agent contained in the antibacterial particles does not always exert a good effect on all bacteria at a fixed amount, and has little effect on a specific type. There is. Therefore, in order to obtain a sufficient effect on various kinds of bacteria, a large amount of antibacterial particles must be added, and as described above, there are problems in cost, mechanical strength of the film, and transparency of the film. Will occur.

The present inventors have conducted intensive studies to solve the above problems, and as a result, have reached the present invention. Antibacterial properties exhibiting good effects on a plurality of types of bacteria with a small amount of antibacterial particles. It is intended to provide a polypropylene-based composite film.

[0007]

According to the present invention, an antibacterial particle is contained on at least one surface of a base layer made of a biaxially stretched film of a resin mainly composed of polypropylene in an amount of 0.05 to 5% by weight.
A composite film in which a surface layer made of a polypropylene-based resin is laminated, wherein the antibacterial particles contain an antibacterial metal or metal ion, and the composite film contains 0.05 to 5% by weight of a nonionic surfactant. The present invention relates to an antibacterial polypropylene-based composite film characterized by containing.

[0008]

Embodiments of the present invention will be described below. The antibacterial polypropylene-based composite film of the present invention comprises a base layer and a surface layer laminated on at least one surface thereof, wherein the surface layer contains antibacterial particles in an amount of 0.05 to 5% by weight.
And the composite film contains 0.05 to 5% by weight of a nonionic surfactant.

The base layer is composed of a biaxially stretched film of a resin mainly composed of polypropylene. As the resin mainly composed of polypropylene, in addition to the polypropylene alone resin, a resin obtained by mixing a resin such as propylene-ethylene copolymer with polypropylene as long as the characteristics of the base layer are not impaired, or a film of these resin components, For the purpose of improving the characteristics of the above, there may be used those blended with known additives such as an antistatic agent, an antifogging agent, a filler, an ultraviolet absorber, an antioxidant and a lubricant. In the case of the “resin mainly composed of polypropylene”, when the mixed resin of polypropylene and other resin is used as the resin component, the weight ratio of the polypropylene in the resin component (the component excluding the additives) exceeds half. Means Also, the base layer is not limited to one layer,
Two or more layers may be used.

The surface layer is made of a polypropylene resin containing 0.05 to 5% by weight, preferably 0.3 to 3% by weight of antibacterial particles. If the amount is less than 0.05% by weight, the dispersion of the antibacterial particles in the surface layer is too small to obtain a good antibacterial effect, while if it is more than 5% by weight, not only the appearance is deteriorated, but also the scratch resistance is deteriorated. .

The antibacterial particles are prepared by converting a metal having antibacterial action (antibacterial metal) such as silver, copper, zinc, gold or platinum or a metal ion into zeolite, aluminum silicate, magnesium oxide, zirconium phosphate, apatite or silica. Calcium acid, diatomaceous earth, talc, supported on an inorganic carrier such as glass, as long as the carrier has antibacterial properties, used without any particular limitation, two or more kinds of antibacterial particles You may mix with a polypropylene resin in the range which becomes 0.05-5 weight% in total. The average particle size of the antibacterial particles is preferably about 0.1 to 10 μm. If it is smaller than 0.1 μm, the probability that the antibacterial particles will be buried in the surface resin increases, whereas if it is larger than 10 μm, not only the appearance deteriorates, but also the scratch resistance deteriorates, and the antibacterial particles easily fall off the surface layer. And cannot be put to practical use.

As the polypropylene resin for the surface layer,
A material composed of polypropylene, a propylene-ethylene copolymer, a propylene butene copolymer, or a material composed of polyethylene, a mixture of polybutene and polypropylene is used. In addition, in addition to the antibacterial particles, various additives other than the antibacterial agent and the filler may be added to the surface layer polypropylene resin.

Examples of the nonionic surfactant include, but are not particularly limited to, glycerin fatty acid esters, condensation products of fatty acids (C _{12 to} C ₁₈ ) with diethanolamine, and alkyldiethanolamines (C _{12 to} C ₁₈ ). Particularly preferred. The amount of the non-ionic surfactant is in the range of 0.05 to 5% by weight, preferably 0.1 to 3% by weight, based on the entire composite film. If the content is less than 0.05% by weight, both the antistatic property and the antifogging property are not sufficient, and the effect on Staphylococcus aureus cannot be sufficiently obtained.
When the amount exceeds the above, not only the appearance of the film is deteriorated due to the excessive surfactant, but also the antibacterial property does not increase so much with the increase of the surfactant, and is not economical. This nonionic surfactant is mixed with the raw materials of all the layers in a required amount during the production of the antibacterial polypropylene-based composite film of the present invention, and is mixed with the raw materials of at least one layer. It may be a film.

The total thickness of the antibacterial polypropylene composite film is 10 to 100 μm, preferably 15 to 60 μm.
μm is preferable, and the thickness of the lamination is preferably 0.5 to 5 μm. The antibacterial polypropylene-based composite film may have a surface property improved by corona treatment, flame treatment, plasma treatment or the like, if necessary.
In order to fully satisfy all the antistatic properties, those subjected to corona treatment are preferable. Examples of the method for forming a composite film include a coextrusion method, an extrusion lamination method, a dry lamination method, a method of laminating a surface layer on a uniaxially stretched base layer, and stretching the film in a perpendicular direction.

The present invention is constructed as described above. When the film of the present invention is laminated on a printing paper or when an article is wrapped using a bag made of the film of the present invention, the antibacterial In addition to its excellent antistatic properties, it is also excellent in antistatic properties, so it is difficult to attract dust in the air, which causes the propagation of various bacteria.In packaging fruits and vegetables, in addition to the above effects, the excellent antifogging effect has a display effect. Enhanced, synergistic effect of nonionic surfactant and antibacterial particles,
It enhances the antibacterial effect of the film surface.

[0016]

EXAMPLES Next, examples of the present invention will be described, but the present invention is not limited to these examples. In the following example,
The obtained film was evaluated by the following method, and the results are shown in Table 1.

<Antibacterial effect> Into a solution obtained by diluting a nutrient broth medium 500-fold with purified water, the bacteria plated on a separately prepared ordinary agar medium are added.
^It was adjusted to be 5-1 × 10 ⁶ / ml. 0.1 ml of this bacterial solution was dropped on a test piece (50 mm x 50 mm), and a polyethylene film (a stomacher plastic bag) cut into 45 mm x 45 mm was placed thereon, followed by culturing at 35 ° C and a humidity of 90% or more. went. SCDL after 24 hours
After washing with 10 ml of P medium, 1 ml was taken out and the number of viable cells per ml was measured by the pour plate method. The bacteria are Escherichia coli IF03972
And Staphylococcus aureus IF01273
2) was used.

<Anti-fogging effect> 200 ° C. of hot water at about 70 ° C.
Pour 150cc into the glass of c and immediately prepare A4
Cover the test bag of the size and evaluate the degree of haze inside the film. The evaluation is a three-level evaluation. A: No fogging occurs. B: Some haze occurs. C: Heavy clouding.

<Antistatic Effect> The antistatic effect is evaluated by measuring the surface resistivity (Ω / port) using a high resistivity meter manufactured by Mitsubishi Chemical Corporation. The numerical values are surface specific resistance values.

Example 1 Surfactant 0.08% by weight, antibacterial particles 0.7% by weight
Example: As a raw material for a base layer, melting point 160 ° C., density 0.91 g / c
Polypropylene 99.9% by weight of m ^3, stearyl diethanolamine (nonionic surfactant) providing a formulation was added 0.1% by weight, and as the surface layer raw material, mp 130 ° C, density 0. A mixture of 89 g / cm ³ of propylene-ethylene random copolymer (99.3 wt%) and 0.7 wt% of silver-supported glass (antibacterial particles) manufactured by Ishizuka Glass Co., Ltd. having an average particle diameter of 0.8 μm. I prepared things. Then, these are extruded from two types and three layers of T dies and stretched in the longitudinal direction, and then guided to a tenter and stretched in the transverse direction. Obtained. The amount of nonionic surfactant in this film is 0.08% by weight
It is. Further, both sides of the film were subjected to a corona treatment and the film was wound. Table 1 shows the evaluation results of the obtained films.

Example 2 0.25% by weight of surfactant, 0.7% by weight of antibacterial particles
Example: As a raw material for a base layer, melting point 160 ° C., density 0.91 g / c
Polypropylene 99.7% by weight of m ^3, stearyl diethanolamine monostearate (nonionic surfactant) 0.2 wt%, stearyl diethanolamine (nonionic surfactant) was added 0.1% by weight formulation Except for using the product, a composite biaxially stretched polypropylene film was obtained in the same manner as in Example 1. The total amount of nonionic surfactant in this film is 0.25% by weight. Further, both sides of the film were subjected to a corona treatment and the film was wound. Table 1 shows the evaluation results of the obtained films.

Example 3 Example of 1.0% by weight of surfactant and 0.7% by weight of antibacterial particles As base material, melting point 160 ° C., density 0.91 g / c
Polypropylene 98.8% by weight of m ^3, glycerol monostearate (nonionic surfactant) 1.0% by weight, stearyl diethanolamine (nonionic surfactant) was added formulation 0.2 wt% Other than using
A composite biaxially oriented polypropylene film was obtained in the same manner as in Example 1. The total amount of nonionic surfactant in this film is 1.0% by weight. Table 1 shows the evaluation results of the obtained films.

Example 4 Example of 1.0% by weight of surfactant and 0.3% by weight of antibacterial particles As raw materials for the surface layer, melting point is 130 ° C., density is 0.89 g /
propylene-ethylene random copolymer 99 cm ^3.
Ishizuka Glass Co., Ltd. with an average particle diameter of 0.8 μm in 7% by weight
A composite biaxially stretched polypropylene film was obtained in the same manner as in Example 3, except that a blend containing 0.3% by weight of silver-making-supporting glass (antibacterial particles) was used. The total amount of nonionic surfactant in this film is 1.0% by weight. Table 1 shows the evaluation results of the obtained films.

Example 5 Example of 1.0% by weight of surfactant and 5% by weight of antibacterial particles As a raw material for the surface layer, melting point is 130 ° C., density is 0.89 g / c.
the propylene-ethylene random copolymer of m ^3, except that the average particle diameter was used 0.8μm of Ishizukagarasu Co. Seigin loaded glass formulation was added (antibacterial particles) 5.0 wt% EXAMPLE In the same manner as in Example 3, a composite biaxially stretched polypropylene film was obtained. The total amount of nonionic surfactant in this film is 1.0% by weight. The resulting film has a poor film appearance due to the effect of a large amount of antibacterial particles, and tends to have poor transparency. Table 1 shows the evaluation results.
Shown in

Example 6 Example of 4.4% by weight of surfactant and 0.7% by weight of antibacterial particles As base material, melting point: 160 ° C., density: 0.91 g / c
Polypropylene 94.8% by weight of m ^3, glycerol monostearate (nonionic surfactant) 4.0% by weight, of stearyl diethanolamine (nonionic surfactant) 0.2% by weight, stearyl diethanolamine mono- A composite biaxially stretched polypropylene film was obtained in the same manner as in Example 3, except that a blend containing 1.0% by weight of stearate (a nonionic surfactant) was used. The total amount of nonionic surfactant in this film is 4.4
% By weight. The resulting film tended to have a somewhat worse appearance due to the large amount of surfactant. Table 1 shows the evaluation results.
Shown in

[Comparative Example 1]-Example in which surfactant and antibacterial particles are 0% by weight Except for using only polypropylene having a melting point of 160 ° C and a density of 0.91 g / cm ³ for both the base layer material and the surface layer material. A composite biaxially oriented polypropylene film was obtained in the same manner as in Example 1. Table 1 shows the evaluation results.

Comparative Example 2 Example of 0% by weight of surfactant and 0.7% by weight of antibacterial particles The raw material for the base layer has a melting point of 160 ° C. and a density of 0.91 g / cm ^3.
A composite biaxially stretched polypropylene film was obtained in the same manner as in Example 1, except that only the polypropylene was used.
Table 1 shows the evaluation results.

Comparative Example 3 Example of 1.0% by weight of surfactant and 0% by weight of antibacterial particles The raw material for the surface layer has a melting point of 130 ° C. and a density of 0.89 g / cm ^3.
A biaxially oriented polypropylene film was obtained in the same manner as in Example 3, except that only the propylene-ethylene random copolymer was used. Table 1 shows the evaluation results.

[0029]

[Table 1]

[0030]

As shown in Comparative Example 2, the antibacterial effect of Gram-positive bacteria, Staphylococcus aureus, is not sufficient with only the antibacterial particles. The drug alone had almost no antibacterial effect on E. coli, a gram-negative bacterium. However, Examples 1 to 6
As shown in the above, the combination of the antibacterial particles and the nonionic surfactant in a predetermined amount not only compensates for each other's drawbacks, but also surprisingly, both Escherichia coli and Staphylococcus aureus significantly improve antibacterial properties. I understood. This is presumably because the formation of the water film by the nonionic surfactant promotes metal ionization of the antibacterial particles, and the antibacterial effect is dramatically improved. Moreover, in the examples, the antifogging effect and the antistatic effect were excellent.

As described above, the antibacterial polypropylene-based composite film of the present invention exhibits a good antibacterial effect against a plurality of types of bacteria even with a small amount of antibacterial particles, and also has excellent antifogging and antistatic effects. It is economical and can be suitably used for lamination of printing paper, packaging of food, and the like.

Claims (1)

[Claims] 1. A composite film comprising a base layer made of a biaxially stretched film of a resin mainly composed of polypropylene and a surface layer made of a polypropylene resin containing 0.05 to 5% by weight of antibacterial particles laminated on at least one surface. The antibacterial particles contain an antibacterial metal or metal ion, and the composite film contains a nonionic surfactant in an amount of from 0.05 to 0.05.
An antibacterial polypropylene-based composite film containing 5% by weight.