JPH1177911A - Tear sheet with antibacterial function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sanitary tear sheet having antibacterial function and productivity of a low cost by preventing adherence and breeding of mold. SOLUTION: The tear sheet comprises a single layer or multilayer structure having a layer made of composition containing olefin polymer including 0.2 to 3 wt.% of antibacterial agent as a main component. The antibacterial agent- containing layer of a surface layer contains 5 to 30 wt.% of conductive fiber. It has antibacterial function of surface resistivity of 10<10> Ω or less, static layer frictional coefficient of 0.1 to 0.6 and thickness of 0.3 to 15 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tear sheet used for stacking containers on a pallet in multiple stages to form a unit. More specifically, the present invention relates to a tear sheet having an antibacterial function, comprising a composition containing an antibacterial agent.

[0002]

2. Description of the Related Art In recent years, steel or aluminum metal containers used for beer, soft drinks, edible oils, cans, etc., glass containers used for pharmaceuticals, industrial chemicals, liquid seasonings and the like, liquid detergents, seasonings, etc. BACKGROUND ART A large variety of containers are used in many fields, such as plastic containers used for ice cream and the like. Most of the cargo handling work such as packing and transporting these containers is mechanized or automated.

[0003] One mode of the above packing and transportation is unit loading. In this method, when packing and transporting containers and the like, they are combined into an appropriate number or weight to form one unit, and unloading is performed by equipment without being destroyed on the way.

That is, after stacking a certain number of containers on a pallet in multiple rows and multiple stages to form a unit, the container is subjected to a cargo handling operation for packing such as shrink packaging and stretch packaging. At this time, a tier sheet is inserted for each stage for the purpose of stabilizing the container, preventing the collapse of the load, or providing antibacterial and dustproof purposes.
Currently, paper sheets are generally used as such tear sheets.

In recent years, for the purpose of maintaining freshness and taste, simplifying the process, and the like, a filling method called aseptic filling, in which a sterilization step is simplified, has been adopted, and the demand for hygiene has been increasing. Therefore, it is conceivable to apply an antibacterial agent to a paper tier sheet that is generally used at present. However, adding an antibacterial agent application step causes poor productivity and a significant increase in cost. In addition, the applied antibacterial agent is lost due to repeated use, and the antibacterial effect is gradually lost. In a paper tear sheet, the mechanical strength such as bending stiffness and impact resistance is reduced due to water absorption, moisture absorption, and the like, so that there is a limit to repetitive use, and there are also restrictions on mechanical strength. Also, because the material is paper,
There are drawbacks such as fuzzing and easy attachment of various bacteria and dust. In addition, since water washing and hot water treatment are not possible, cleaning by air shower, brushing, etc.
In sterilization treatments such as flame treatment and hot roll treatment, sufficient bacteria elimination and dust prevention cannot be performed.Therefore, when palletizing and transporting unfilled containers, it is inevitable that these germs and the like enter the containers. There have been problems with the use of paper tear sheets, especially in the fields of food, medicine and the like.

[0006] As plastic materials, there are those proposed in International Publication No. WO82 / 01861 and the like, but since these tear sheets are made of plastic, they are remarkably charged, attract dust, and are hardly dropped. Trouble easily occurs. Therefore, a plastic tear sheet having permanent antistatic performance is disclosed in Japanese Patent Publication No. Hei 8-13527. However, since this tear sheet does not have an antibacterial function, it is effective in preventing dust and dirt due to static electricity. Although it could prevent adhesion, it did not have antibacterial and antifungal functions, and thus could not prevent the generation of bacteria and mold.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and prevents the adhesion and propagation of bacteria and mold, and provides an antibacterial function which can be produced hygienically and at low cost. It is intended to provide a tier sheet having the following.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to achieve the above object, and as a result, formed a sheet surface of a tear sheet composed of a composition containing an olefin polymer as a main component. It has been found that an antimicrobial function can be imparted by including an antimicrobial agent in the raw material composition. Furthermore, by making the tear sheet permanent-chargeable,
Antibacterial function is further improved.

The antimicrobial function of the permanent antistatic tear sheet having the antimicrobial function of the present invention is considered as follows.

[0010] Bacteria and molds adhere and proliferate based on contaminants such as dirt and dust attached to the sheet surface.

[0011] Since the tear sheet of the present invention contains conductive fibers, static electricity is less likely to be generated, and as a result, dirt and dust in the air are less likely to adhere.

Further, since the antibacterial agent is blended in the tear sheet of the present invention, rarely attached bacteria, molds, etc. are killed by the antibacterial agent.

Regarding the antibacterial function against bacteria and mold, for example, in the case of zeolites and silicate-based antibacterial agents, when bacteria and the like come into contact with silver ions eluted from zeolite carrying silver / zinc ions, silver ions are intracellularly contained in bacteria and the like It is taken up by bacteria and binds to enzymes that are important for the growth of bacteria, etc., and exerts antibacterial and antifungal effects by losing oxygen activity.

The first aspect of the present invention is to provide an antibacterial agent in an amount of 0.2 to 3 wt.
The present invention relates to a tear sheet having an antibacterial function, which is a tear sheet having a single-layer or multilayer structure having a layer composed of a composition mainly containing an olefin-based polymer containing 0.1%.

A second aspect of the present invention relates to a tear sheet having an antibacterial function, wherein at least one surface layer has a multilayer structure composed of a composition containing an antibacterial agent.

A third aspect of the present invention is that the tear sheet comprises 0.2 to 3% by weight of an antibacterial agent and 5 to 5% of conductive fibers on one or both sides of a sheet composed of a composition containing an olefin polymer as a main component. A thermoplastic resin film containing 30 wt% is laminated and has a total thickness of 0.3 to 1
5 mm, the surface resistivity of the exposed surface of the thermoplastic resin film containing the conductive fiber is 10 ¹⁰ Ω or less, and the coefficient of static friction of the surface in contact with the container bottom is in the range of 0.1 to 0.6. And a tear sheet having an antibacterial function.

A fourth aspect of the present invention relates to a tear sheet having an antibacterial function, wherein the olefin polymer is a polypropylene polymer having a melt flow rate of 0.1 to 20 g / 10 minutes.

A fifth aspect of the present invention relates to a tear sheet having an antibacterial function, wherein the thermoplastic resin film is made of a thermoplastic resin containing a polypropylene polymer as a main component.

A sixth aspect of the present invention relates to a tear sheet having an antibacterial function, wherein the composition contains an inorganic filler.

A seventh aspect of the present invention has an antibacterial function wherein the inorganic filler is talc and is contained in an amount of 5 to 30 parts by weight based on 100 parts by weight of the olefin polymer. Related to the tier sheet.

An eighth aspect of the present invention relates to a tear sheet having an antibacterial function, wherein the conductive fibers are carbon fibers and / or metal fibers.

A ninth aspect of the present invention is the tear sheet, wherein 0.1 to 10 parts by weight of titanium dioxide is blended as a hiding agent with respect to 100 parts by weight of the olefin polymer. The present invention relates to a tear sheet having an antibacterial function.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION As the antibacterial agent used in the present invention,
There are organic antibacterial agents and inorganic antibacterial agents.Organic antibacterial agents include organotin compounds, diphenyl ether type, chlorhexidine type, etc., and inorganic antibacterial agents include cuprous oxide, copper rhodanide, zeolite containing metal ions. Silicates, zirconium phosphates, soluble glasses and silica gels. It may be organic or inorganic, but from the viewpoint of persistence of antibacterial function and toxicity to the human body,
Preferably, an inorganic material, in particular, a material in which a metal having a bactericidal effect such as silver, copper, or zinc is supported on zeolite or silicate is suitably used. Among them, Ag-Zn based, Ag-
Cu-based materials are particularly preferred.

As a method of containing an antibacterial agent, an antibacterial agent may be applied to the surface of the formed tear sheet.
Forming a sheet by adding an antimicrobial agent to the raw material before molding is simpler and can reduce costs.

The content of the antibacterial agent is not particularly limited as long as the antibacterial function is exhibited, but is preferably in the range of 0.2 to 3% by weight based on the olefin polymer containing the antibacterial agent. If it is less than 0.2 wt%, the antibacterial effect is not sufficient, and if it is more than 3, the effect is less manifested with respect to cost increase.

The tear sheet of the present invention has a layer composed of a composition comprising an olefin polymer containing the above antibacterial agent as a main component, and has a single-layer structure, a two-layer structure of a surface layer and a core layer. A three-layer structure in which a surface layer is provided on both sides of a core layer, or a multilayer structure including four or more layers having a plurality of layers between the surface layers.

In a tear sheet having a multilayer structure, the antibacterial agent may be contained in at least one surface layer of a surface layer or three or more layers. In the case of a single-layer structure composed of an olefin resin containing an antimicrobial agent as a main component, the antimicrobial agent is uniformly dispersed in the sheet, and is dispersed not only in the surface layer but also in the sheet. Will be. Since the antibacterial agent present on the surface actually exerts the antibacterial function, the antibacterial agent present inside the sheet far from the surface does not function sufficiently especially in a thick sheet. To make effective use of the added antimicrobial agent to reduce the amount of antimicrobial agent used and reduce costs,
It is preferable that at least one surface layer has a multilayer structure containing an antibacterial agent.

As a specific method of producing a multilayered tear sheet, for example, a layer containing an antibacterial agent is laminated on one or both sides of a sheet mainly composed of an olefin polymer by adopting a coextrusion molding method or the like. To be integrally formed.

As the olefin polymer, low,
Medium, homopolymers such as high-density polyethylene, polypropylene, polybutene-1, poly-4-methylpentel-1, and other α-containing ethylene or propylene as a main component.
Examples include polyolefin-based resins such as copolymers with olefins and mixtures thereof.

From the viewpoints of heat resistance, mechanical strength such as bending rigidity and impact resistance, etc., a crystalline polymer or an ethylene polymer comprising an olefin having 3 or more carbon atoms;
Alternatively, a mixture of them and another olefin polymer is preferable, and particularly a propylene homopolymer or a propylene polymer composed of a block copolymer or a blend thereof, or a propylene polymer and an ethylene polymer. Is preferably a mixture of

In order to improve the impact resistance, particularly the low-temperature impact characteristics, etc., the above-mentioned polymer may be added to the above-mentioned polymer if necessary.
Synthetic rubbers such as diene copolymer rubber, butyl rubber and polyisobutylene, and elastomers such as natural rubbers can also be mixed.

The MFR of the above propylene polymer (JIS)
Melt flow rate according to K6758) 0.1 to 20
g / 10 minutes, and more preferably 0.3 to 15 g / minute. If the MRF is less than 0.1 g / 10 minutes, the flowability of the molten resin is poor, and it is difficult to produce a good sheet.
In the case of more than / 10 minutes, the web of the molten resin hangs down, and it is difficult to perform good molding. In addition, there is a concern that the strength and other physical properties of the sheet are reduced.

The thermoplastic resin film containing conductive fibers of the present invention is a film obtained by blending conductive fibers with a thermoplastic resin, and has a thickness of 30 to 500 μm, and more preferably 50 to 200 μm. preferable. The thermoplastic resin includes a polyolefin resin, a polyamide resin, a polyester resin, a vinyl chloride resin, a saponified ethylene-vinyl acetate copolymer, a polyvinyl alcohol resin, and a mixture thereof. Especially cold-resistant,
Various physical properties such as mechanical strength are good, and polyolefin resins as described above in terms of inexpensiveness, especially propylene homopolymers, mainly composed of propylene polymers composed of block copolymers and the like. Are preferred.

Examples of the conductive fiber in the present invention include carbon fiber, metal fiber made of aluminum, brass, stainless steel, etc., metallized glass fiber obtained by coating glass fiber with silver, copper, etc., and metal such as silver, copper, brass, tin, etc. Synthetic fibers mixed with a powder may be used. Among them, carbon fiber is most preferable from the viewpoint of performance and economy.
In addition, the fibers may be any of short fibers and long fibers,
A long fiber that has a remarkable effect even with a small amount is more preferable.

The content of the conductive fiber is 5 to 30% by weight, preferably 7 to 20% by weight, based on the thermoplastic resin forming the thermoplastic resin film. If the fiber content is less than 5% by weight, the surface resistivity of the sheet exceeds 10 ¹⁰ Ω, and the antistatic effect cannot be satisfied. Also,
If the content exceeds 30% by weight, the antistatic effect can be satisfied, but the sheet becomes dark and the appearance deteriorates.

In order to impart conductivity to the tear sheet of the present invention, a thermoplastic resin film containing the above-mentioned conductive fiber on one or both sides of a sheet comprising the composition containing the olefin polymer as a main component is used. It is integrally molded by laminating by adopting a co-extrusion molding method or the like.
The sheet integrated in this way can suppress charging on the other surface only by laminating the conductive film on only one surface (generally, this phenomenon is called a tunnel effect). In this case, since the antibacterial function is not exhibited unless the antibacterial agent is present on the surface, the antibacterial agent must also be contained in the thermoplastic resin film layer.

Further, in order to facilitate the movement of empty cans and the like when performing multi-stacking, it is preferable that the friction coefficients of the front and back surfaces of the sheets are different. For this purpose, the entire surface or a desired portion of one side may be roughened by embossing, sandblasting, or the like, or may be made different by bonding or laminating an anti-slip material such as an ethylene-vinyl acetate copolymer or a synthetic rubber. desirable.

The above-mentioned coefficient of friction varies depending on the type of metal container, glass container or plastic container, the shape of the container bottom, the weight of the container, and the like. 6, preferably 0.2 to
A range of 0.5 is appropriate.

The thickness of the tear sheet of the present invention is 0.3 to 1 as a whole in both cases of a single layer and a multilayer.
A range of 5 mm is appropriate. For example, in the case of a three-layer structure having a surface layer on both sides of the core layer, the surface layer has a thickness of 0.0
It is preferably about 5 to 0.5 mm. If the total thickness is less than 0.3 mm, the mechanical strength such as the rigidity of the sheet is not sufficient, and if it exceeds 15 mm, the weight of the sheet increases, which may hinder automation and handling of cargo handling.

The antistatic performance of the tear sheet of the present invention is preferably such that the surface resistivity is 10 ¹⁰ Ω or less. When the surface resistivity exceeds 10 ¹⁰ Ω, the antistatic effect is low, and dust is easily attracted.

The tear sheet of the present invention preferably contains an inorganic filler in the composition. The inorganic filler used may be powdery, granular, flat, scale-like, or the like.
Needle-like, spherical or hollow, fibrous, fibrous fabrics, etc., and specific examples thereof include calcium carbonate, magnesium carbonate, calcium sulfate, calcium silicate, barium sulfate, aluminum hydroxide, and aluminum hydroxide. Magnesium, calcium hydroxide, calcium sulfite, mica, clay, diatomaceous earth, talc, zeolite, zinc oxide,
Titanium oxide, molybdenum sulfide, quartz powder, pentonite,
Alumina, silica sand, iron oxide, metal powder, antimony trioxide,
Powdery and granular fillers such as graphite, silicon carbide, silicon nitride, silica, boron nitride, aluminum nitride, white carbon, carbon black, glass beads, glass powder, silica stone, mica, glass plate, sericite, pyrophyte, aluminum flake, Other metallic foils, flat or flaky fillers such as graphite, hollow fillers such as shirasu balloons, metal balloons, glass balloons, pumice stones, and minerals such as glass fibers, whiskers, silicon carbide fibers, asbestos, and wollastonite Examples of fibrous fillers such as fibers can be given.

Of the above-mentioned inorganic fillers, talc is most preferably used in combination from the standpoint of mechanical properties such as heat resistance and flexural modulus and tear sheet such as workability, and the particle size is 2 to 10 μm. Is preferable. When the particle size exceeds 10 μm, there is a concern that the impact strength is reduced. When the particle size is less than 2 μm, it is preferable in terms of physical properties but is expensive and economically disadvantageous.

The amount of the inorganic filler can be appropriately selected within the range of 5 to 30 parts by weight based on 100 parts by weight of the olefin polymer. When the amount of the inorganic filler is less than 5 parts by weight, required physical properties such as heat resistance cannot be satisfied. On the other hand, when the amount exceeds 30 parts by weight, there is a concern that the mechanical strength is reduced, which is not preferable.

In particular, in the present invention, various colorable tear sheets can be obtained by blending a shielding agent such as titanium dioxide into the thermoplastic resin film layer containing conductive fibers. The blending amount of the concealing agent is 100 thermoplastic resin.
It is preferable to mix in a range of 0.1 to 10 parts by weight with respect to part by weight.

Further, in the present invention, when compounding the tear sheet raw material, the kneadability and the moldability of the tear sheet are improved, and the weather resistance, bending rigidity, impact resistance, heat resistance, To improve color tone, gloss, surface properties such as scratch resistance, printability, paintability, etc., use ordinary antioxidants, ultraviolet absorbers, dispersants, lubricants, crosslinking agents, organic or inorganic pigments, etc. Additives may be added.

The composition of the above-mentioned tear sheet raw material can be carried out using a kneader such as a single screw extruder, a twin screw extruder, a Banbury mixer, a roll, a kneader or the like, and is easily formed into a sheet using a T-die extruder. can do.

Further, the surface of the tear sheet is used to improve mechanical strength such as bending rigidity in one direction, or by adjusting the contact area with the container so that the direction of the container is arranged on the tear sheet. In order to give it, fine unevenness processing may be performed at the time of forming a tear sheet.

The shape of the tear sheet of the present invention may be any suitable shape such as a rectangle, square, ellipse, and circle. In the case of a shape having corners such as a rectangle and a square, a container is formed at each corner. It is desirable to attach a radius that matches the Further, holes for draining can be formed at desired positions of the tear sheet to such an extent that required physical properties such as bending rigidity are not impaired.

[0049]

EXAMPLES The present invention will now be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto. The performance of the tear sheet was evaluated for antibacterial properties by the following method.

<Test Methods> Silver Inorganic Antibacterial Agents Study Group, "Self-Specific Standards for Silver Inorganic Antibacterial Agents and Antibacterial Testing Methods, Antibacterial Testing Methods for Antibacterial Products I (1995 Edition) Film Mounting Method" (J. A.)
ntibact. Antifung. Agents. Vol / 25, No.3, PP.163 〜
167, 1997), 0.5 mL of the bacterial suspension conditioned with a medium was taken on each test sample, covered with a coating film, covered, and left at 35 ° C. for 24 hours. The number of viable bacteria was measured.

Test sample: 50 × 50 mm Medium: Phosphate buffer solution + 1 / 500-fold nutrient Test bacteria: Escherichia coli, Staphylococcus aureus

Examples 1 and 6 As the polypropylene polymer forming the core layer (MFR
= 1.7 g / 10 minutes Trade name: J-Aroma E720
N, manufactured by Nippon Polyolefin Co., Ltd.) and used for a thermoplastic resin film for forming a surface layer, a polypropylene-based polymer (MFR = 1.7 g / 10 min, trade name: J-Alomer E720N, manufactured by Nippon Polyolefin Co., Ltd.) Mixture of)) and (MFR = 1.5 g / 10 min, trade name: J-Aroma E120G, manufactured by Nippon Polyolefin Co., Ltd.)
Was used. Further, in the thermoplastic resin film layer, carbon fiber (trade name: Granock, manufactured by Nippon Oil Co., Ltd., diameter 7 μm, fiber length 0.2 mm) as a conductive fiber in the resin 10
wt%, titanium dioxide (JIS K5116) as a hiding agent
0.5 wt% of rutile type 1) specified as described above, and 0.1% of Ag-Zn-based AIS-NAZ310 as an antibacterial agent.
wt.%, kneaded with a twin screw extruder (diameter 65 mm), and a resin temperature of 240 with a T-die extruder (diameter 90 mm).
° C, chill roll temperature 70 ° C, take-off speed 1.5m /
A laminated sheet having a thickness of 1.0 mm (film layer / sheet layer / film layer: 0.1 / 0.8 / 0.1) and a width of 1500 mm was formed. 1440mm x 11 from this sheet
A tear sheet having a radius of 30 mm and each corner having a radius of 25 mm was formed. Next, the surface of the resin film containing conductive fibers is embossed with an embossing roll,
The tear sheets of the present invention of Examples 1 and 6 were obtained so that the coefficient of static friction was 0.3. Table 1 shows the results of an antibacterial test performed using the tear sheet.

Examples 2 and 7 Examples 1 and 6 with the content of the antibacterial agent being 0.2 wt%
Table 1 shows the results of preparing a tear sheet and conducting an antibacterial test in the same manner as described above.

Examples 3 and 8 Examples 1 and 6 with the content of the antibacterial agent being 0.5 wt%
Table 1 shows the results of preparing a tear sheet and conducting an antibacterial test in the same manner as described above.

Examples 4 and 9 Examples 1 and 6 with the content of the antibacterial agent being 1.0 wt%.
Table 1 shows the results of preparing a tear sheet and conducting an antibacterial test in the same manner as described above.

Examples 5 and 10 Examples 1 and 6 with the content of the antibacterial agent being 2.0 wt%
Table 1 shows the results of preparing a tear sheet and conducting an antibacterial test in the same manner as described above.

Comparative Examples 1 and 2 A tear sheet was prepared in the same manner as in Examples 1 and 6 except that no antibacterial agent was contained, and the results of the antibacterial test were shown in Table 1.
1 is shown.

[0058]

[Table 1]

[0059]

Since the permanent antistatic tear sheet having an antibacterial function of the present invention has an excellent antibacterial function, it prevents bacteria and mold from adhering and growing, and exhibits excellent hygiene performance. In the case of a multilayer structure, the amount of the antibacterial agent used can be reduced, and production can be performed at low cost. In addition, since it is water-resistant, it can withstand repeated use by washing, and it gives permanent antistatic performance without using carbon black, so it has excellent appearance, and it is also suitable for fields such as pharmaceuticals and foods requiring hygiene. Can be used.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08J 5/18 CES C08J 5/18 CES

Claims (9)

[Claims] An antibacterial function characterized by a single-layer or multi-layer tear sheet having a layer composed of a composition mainly composed of an olefin polymer containing 0.2 to 3% by weight of an antibacterial agent. Tier sheet to have. 2. The tear sheet having an antibacterial function according to claim 1, wherein at least one surface layer has a multilayer structure composed of a composition containing an antibacterial agent. 3. The anti-microbial agent according to claim 1, wherein the tear sheet is a sheet composed of a composition mainly composed of an olefin-based polymer, and one or both surfaces of the sheet is provided with 0.2 to 3 wt% of an antibacterial agent and 5 to 5% of conductive fibers.
A thermoplastic resin film containing 30 wt% is laminated, the overall thickness is 0.3 to 15 mm, and the surface resistivity of the exposed surface of the thermoplastic resin film containing the conductive fiber is 10 ¹⁰ Ω or less. The tear sheet having an antibacterial function according to claim 1 or 2, wherein a coefficient of static friction of a surface in contact with the bottom of the container is in a range of 0.1 to 0.6. 4. The tier having an antibacterial function according to claim 1, wherein the olefin-based polymer is a polypropylene-based polymer having a melt flow rate of 0.1 to 20 g / 10 minutes. Sheet. 5. The tear sheet having an antimicrobial function according to claim 1, wherein the thermoplastic resin film is made of a thermoplastic resin containing a polypropylene-based polymer as a main component. . 6. The tear sheet having an antibacterial function according to claim 1, wherein the composition contains an inorganic filler. 7. The antibacterial function according to claim 6, wherein the inorganic filler is talc and is contained in an amount of 5 to 30 parts by weight based on 100 parts by weight of the olefin polymer. Tier sheet to have. 8. The tear sheet having an antibacterial function according to claim 3, wherein the conductive fibers are carbon fibers and / or metal fibers. 9. The tear sheet according to claim 3, wherein 0.1 to 10 parts by weight of titanium dioxide is blended as a hiding agent with respect to 100 parts by weight of the olefin polymer. 8. A tear sheet having an antibacterial function according to any one of 8.