JPH10101128A - Tying strap - Google Patents

Abstract

(57) [Summary] [Problem] To provide a tying cord that has a small product loss rate, has a smaller tearing force, and can be linearly torn at a constant width. A crystalline polyolefin (A ₁₎ 70~9
On at least one surface of 9% by weight and inorganic fine powder core layer of (A ₂₎ a resin composition containing a 30 to 1% by weight as a base (A),. 35 to the inorganic fine powder (B ₂₎ 60% by weight
And a crystalline polyolefin (B ₁₎ 65~40 wt%
The laminated film on which the surface layer (B) made of the resin composition containing is laminated is coated with a crystalline polyolefin (A ₁ , B
The opacity (JIS Z-872) of a uniaxially stretched laminated film obtained by stretching three to ten times in the uniaxial direction at a temperature lower than the melting point of ₁ ) to form many independent fine voids in each layer.
2) is 70% or more, and the product name, barcode, manufacturer, etc. are printed on the surface of the surface layer (B) of the uniaxially stretched multilayer film having an Elmendorf stretching strength (JIS K-7128) of 5 to 15 g in the stretching direction. And a tie strap having a pressure-sensitive adhesive layer provided on the back surface of the uniaxially stretched multilayer film on the side opposite to the printing surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binding tying for a tying string of vegetables such as lettuce, asparagus, leek, leek, burdock, spinach, or a bag containing contents such as bread and industrial parts. It is about strings.

[0002]

2. Description of the Related Art Conventionally, as such a binding string (1), a synthetic paper having a laminated structure of a polypropylene uniaxially stretched film containing an inorganic filler / a biaxially stretched polypropylene film / a polypropylene uniaxially stretched film containing an inorganic filler has been known. No. 46-40794), the vegetable name, manufacturer,
A bar code or the like is printed (2), and a pressure-sensitive adhesive layer such as butyl rubber or an acrylic resin is formed on the side opposite to the printing surface (5).
And a white solid printing on the surface of a binding string (1) (see FIGS. 1 and 2) provided with a notch (4) on a sheet provided with a release paper (6) or a transparent polypropylene unstretched film (CPP); Further, a vegetable name, a manufacturer, a bar code, and the like are printed on the white solid printing surface, and a pressure-sensitive adhesive layer is provided on the opposite side of the printing surface, and a roll-wound sheet is provided with perforations (4 ' ), And a tying strap (1) (see FIGS. 3 and 4) which is further divided into widths per tying strap is used.

[0003]

The binding cord made of synthetic paper as a base material has the advantages that only the notch processing is required, the processing cost is lower than the CPP perforation processing, and the tear strength is low. However, synthetic paper is one-axis / 2-axis / 1
Since the web width is 2 to 3.5 m in the laminated structure of the shaft, if it is cut off from the notch, the central part of the synthetic paper web (the degree of orientation distribution is uniform) during the production of synthetic paper is used. In the case of a tied cord, it can be torn to a uniform width, but when using the end portion of the synthetic paper stock (the direction of stretching orientation is curved toward the end from the center of the synthetic paper) Since the tearing direction is curved, the cut width of the tying cord is not uniform, so that the synthetic paper at the end cannot be used as a raw material for the tying cord, so that the product loss rate becomes 50%, There is a disadvantage that the cost of the string increases. An object of the present invention is to provide a tying cord which has a small product loss rate, and can be linearly torn with a constant tearing width with a smaller tearing force.

[0004]

According to the present invention, 70-99% by weight of a crystalline polyolefin (A ₁ ) is mixed with an inorganic fine powder (A ₁ ).
₂ ) An inorganic fine powder (B) is formed on at least one surface of a core material layer (A) having a resin composition containing 30 to 1% by weight as a base material.
₂ ) 35-60% by weight of crystalline polyolefin (B
₁ ) A laminated film on which a surface layer (B) made of a resin composition containing 65 to 40% by weight is laminated is uniaxially heated at a temperature lower than the melting point of the crystalline polyolefin (A ₁ , B ₁ ). Opacity (JIS P-813) obtained by stretching 10 times and forming many independent fine voids in each layer.
8) is 70% or more, and a manufacturer, a product name, a barcode, etc. are printed on the surface of the surface layer (B) of the uniaxially stretched laminated film having an Emmendorf tear strength (JIS K-7128) of 5 to 15 g in the stretching direction. The present invention provides a binding string having a structure in which a pressure-sensitive adhesive layer (5) is provided on the back surface of the uniaxially stretched multilayer film opposite to the printing surface.

[0005]

The notch is provided along the stretching direction of the uniaxially stretched laminated film. Therefore, when a force is applied to the binding straps 1 and 1, the stress concentrated on the notch is concentrated and applied in the stretching orientation direction of the laminated film. Therefore, each of the binding straps can be cut with a constant width in a straight line direction with a smaller force than a binding strap using a conventional synthetic paper as a base material. In a conventional binding strap made of synthetic paper, since the base layer is a biaxially stretched film, the stress applied to the notch provided in the stretching direction (lateral direction) of the uniaxially stretched film on the front and back layers is limited to the base layer. The tensile strength of the biaxially stretched film in the longitudinal direction of the biaxially stretched film is increased, so that the tear strength is greater than that of the tying cord of the present invention. Alternatively, the back layer may be peeled from the base layer.

[0006]

DETAILED DESCRIPTION OF THE INVENTION (I) Uniaxially stretched multilayer film The uniaxially stretched multilayer film of the present invention is based on a resin composition containing 70 to 99% by weight of a crystalline polyolefin and 30 to 1% by weight of an inorganic fine powder. A laminated film in which a surface layer (B) made of a resin composition containing 35 to 60% by weight of an inorganic fine powder and 65 to 40% by weight of a crystalline polyolefin is laminated on at least one surface of the core layer (A). Is stretched 3 to 10 times in a uniaxial direction at a temperature lower than the melting point of the crystalline polyolefin to form a large number of independent fine voids in each layer.
g of uniaxially stretched laminated film.

(A) Core layer (A): The crystalline polyolefin (A ₁ ) used in the core layer (A) of the uniaxially stretched multilayer film has a crystallinity of 20 to 75%, preferably 30%. -70%, and having 2-8 carbon atoms such as ethylene, propylene, butene-1, hexene-1, octene-1, heptene-1, 4-methylpentene-1, and 3-methylpentene-1. Examples thereof include homopolymers of α-olefins and copolymers of two or more α-olefins.

Specifically, high density polyethylene, propylene homopolymer, ethylene / propylene copolymer, propylene / butene-1 copolymer, poly (4-methylpentene-1), propylene / ethylene / butene-1 And a propylene / 3-methylpentene-1 copolymer. Above all, the melting point (peak temperature of the DSC curve) is 160 to 180 ° C., and the melt flow rate (JIS K7)
210: 230 ° C., 2.16 kg load) 0.5 to 20
A propylene homopolymer of g / 10 minutes, poly (4-methylpentene-1) is particularly preferred.

As the inorganic fine powder (A ₂ ), calcium carbonate, calcined clay, diatomaceous earth, talc, titanium oxide, barium sulfate, aluminum sulfate, silica and the like have an average particle size of 10 μm or less, preferably 0.1 to 4 μm. Things can be exemplified. When the content of the inorganic fine powder is less than 1%, an opaque film having an opacity of 70% or more cannot be obtained. On the other hand, when the content exceeds 30% by weight, fine voids due to stretching are too large and the tensile elasticity in the stretching direction is too large. The rate is low and the strength of the tying string is insufficient.

(B) Surface layer (B): As the inorganic fine powder (B ₂ ) of the surface layer, the inorganic fine powder mentioned for the base material layer (A) can be used. The inorganic fine powder of the surface layer and the base material layer may be of the same type or different types. As the crystalline polyolefin (B ₁ ) of the surface layer, the same type as the crystalline polyolefin used for the base material layer (A) is used. From the viewpoint of cost, propylene homopolymer, propylene / ethylene random copolymer, density There high density polyethylene 0.950~0.970g / cm ³ are preferred. When the content of the inorganic fine powder in the surface layer (B) is less than 35% by weight, the tearing force of the tying string increases. Conversely, if the content exceeds 60% by weight, the roll stretchability becomes poor. The uniaxially stretched multilayer film can be produced, for example, by the following method.

The resin composition of the core material layer (A) and the resin composition of the surface layer (B) are melt-kneaded using separate extruders, and supplied to one co-extrusion die. It is co-extruded into a sheet, cooled once to 10 to 60 ° C, and reheated to a temperature 5 to 50 ° C lower than the melting point of the crystalline polyolefin used for the core material layer. It is obtained by stretching 3 to 10 times using the peripheral speed difference of the roll group in the direction. If necessary, an annealing treatment, a corona discharge treatment, a flame treatment, a plasma treatment and the like are performed. The uniaxially stretched multilayer film thus obtained has a void ratio of 8 to 45%, preferably 15 to 40%, calculated by the following equation.
Has a large number of fine voids in the range of

[0012]

(Equation 1)

The thickness of the uniaxially stretched multilayer film is such that the thickness of the core layer (A) is 20 to 150 μm, preferably 30 to 150 μm.
120 μm, the thickness of the surface layer (B) is 1 to 30 μm, preferably 5 to 30 μm, and the total thickness is 30 to 200 μm.
μm, and preferably 50 to 120 μm in terms of cost. The uniaxially stretched laminated film has an opacity (J
IS Z-8722) is 70% or more, preferably 80 to
100%, the tensile strength in the stretching direction is 5 to 15 g, and the tensile modulus in the stretching direction (JIS P-71).
27) is 18,000-40,000 kgf / cm ² ,
Preferably from 20,000 to 35,000 kgf / cm ²
Of the range.

[Printing Layer] On the surface layer (B) of the uniaxially stretched laminated film, a manufacturer, a trade name, a bar code and the like are printed. (II) Tying String Group As shown in FIG. 1, the binding string group is provided with a notch such that stress is concentrated in the stretching direction (machine direction; longitudinal direction) of the uniaxially stretched laminated film. By tearing each piece in the opposite direction with a finger, a tie of individual pieces is obtained.

[Pressure-Sensitive Adhesive] As the pressure-sensitive adhesive, a known pressure-sensitive adhesive can be used. In particular,
Casein, polyvinyl alcohol, various processed starches, polyacrylamide, carboxymethylcellulose, methylcellulose, carboxy-modified styrene / butadiene latex, acrylonitrile / butadiene latex,
Examples include rubber-based pressure-sensitive adhesives such as methyl methacryl-butadiene latex, acrylic-based pressure-sensitive adhesives such as acrylate-based resin emulsions, silicone-based pressure-sensitive adhesives, and vinyl-based pressure-sensitive adhesives. Among these adhesives, it is preferable to use a rubber-based adhesive. The pressure-sensitive adhesive has a solid content of 25 to 150 g / m ² , preferably 50 to 120 g / m ² .
g / m ² to form a wall thickness of 20 to 140 μm, preferably 45 to 110 μm. Further, the pressure-sensitive adhesive may be formed in advance on the surface of the release paper and bonded to the uniaxially stretched laminated film.

[Release paper] Pulp paper formed on one or both sides with polyethylene, polyvinylidene chloride, clay-containing binder, various fillers such as PVA, starch and CMC, and a film such as silicone oil Is generally used,
Facilitates storage of the tying string group. The thickness of the release paper is usually
It is in the range of 40 to 250 μm, preferably 100 to 150 μm.

[0017]

The binding string using the uniaxially stretched multilayer film of the present invention will be described more specifically with reference to examples and comparative examples. [1] Evaluation method Evaluation of physical properties in Examples and Comparative Examples was performed by the following methods. Tear elastic modulus According to JIS K-7127 (measuring temperature 23 ° C). Opacity According to JIS Z-8722. Density According to JIS P-8118. Whiteness According to JIS L-1015.

UV offset ink printability UV offset printing ink “BC manufactured by T & K Toka Co., Ltd.
-161S "(trade name) and a UV form printing machine manufactured by Akira Seisakusho Co., Ltd., and performing four-color (black, blue, red, and yellow) UV offset printing on the surface side of the uniaxially stretched multilayer film (synthetic paper). The transferability of the ink and the adhesion of the ink were evaluated by the following methods. (1) Transferability of Ink The dot portion of each color was magnified with a magnifying glass (30 times), and the dot reproducibility was visually determined.

(2) Adhesiveness of ink Adhesive tape "Cellotape" (trade name) manufactured by Nichiban Co., Ltd.
Was strongly adhered to the printing surface, and was quickly peeled off along the printing surface, and the degree of ink detachment from the synthetic paper surface was visually determined.

[2] Examples (Example 1) Manufacture of a tying cord composed of a uniaxially stretched multilayer film Propylene homopolymer 60 having a melt flow rate (MFR) of 1 g / 10 min, a crystallinity of 67% and a melting point of 167 ° C.
Parts by weight, a composition comprising 20 parts by weight of high-density polyethylene having a melting point of 134 ° C. and 20 parts by weight of calcium carbonate having an average particle size of 1.5 μm is melt-kneaded by an extruder set at 250 ° C. It was supplied to a coextrusion die for (A). Another extruder set at 250 ° C.
Composition (B) in which 37 parts by weight of calcium carbonate having an average particle size of 1.5 μm and 3 parts by weight of titanium oxide are blended with 60 parts by weight of a propylene homopolymer having a crystallinity of 64 g and a melting point of 167 ° C. at a rate of 10 g / 10 minutes. Is melt-kneaded at 240 ° C., supplied to a co-extrusion die, and extruded in a sheet shape in such a manner as to be laminated on both sides of the composition for the base material layer (A). This was cooled to obtain an unstretched sheet having a three-layer structure (B / A / B).

Next, the unstretched sheet having the three-layer structure is
The film is stretched 5 times in the machine direction by a longitudinal stretching machine composed of rolls having different peripheral speeds set at 35 ° C., then annealed at a temperature of 150 ° C., cooled to a temperature of 50 ° C., and the ears are cooled. Slit to 80 μm (B / A / B = 5/70 /
A uniaxially stretched three-layer film (B / A / B) having fine independent voids (5 μm) was obtained. The uniaxially stretched three-layer film had a void ratio of 28% and an opacity of 85%.
The tensile modulus is 29,600 kgf / c in the stretching direction.
m ^2, transverse 8,900kgf / cm ^2, Elmendorf tear strength when stretching direction is converted thickness at 8 g 100 g
/ Mm.

On the surface of the uniaxially stretched three-layer film, a manufacturer, a trade name, and a bar code were subjected to UV offset printing. Next, a notch having a length of 8 mm was provided at one end of the printed material in the stretching direction at every 15 mm width (see FIG. 1). Next, an adhesive tape to which a release paper having a width of 15 mm was adhered so as to cover the cut portion on the opposite side of the printing surface was bonded to form a binding string group (see FIG. 2). The release paper was peeled off, and then the spine leaves were bundled with one piece of the strap obtained by cutting the strap with a finger. There was no cutting of the tied straps, and the spinach did not come apart (see FIG. 3).

(Comparative Example 1) In Example 1, synthetic paper "Yupo FPG80" having a laminated structure film of uniaxial stretching / biaxial stretching / uniaxial stretching manufactured by Oji Yuka Synthetic Paper Co., Ltd. was used as the synthetic paper.
(Thickness: 80 μm; trade name), except that ") was used to produce a binding string sheet. The physical properties were as shown in Table 1. (Comparative Example 2) A commercially available binding string [white solid printing is performed on the surface of a non-stretched polypropylene film (CPP), and the product name, manufacturer, and barcode are printed by gravure indigo printing, and the pressure-sensitive adhesive is gravure on the back surface. Coated with a roll)
Table 1 shows the physical properties of the compound. (Examples 2 and 3) In Example 1, the stretching ratio was
A binding string was obtained in the same manner except that the amount of calcium carbonate and the lip width of the die were as shown in Table 1.

Example 4 A binding string was obtained in the same manner as in Example 1, except that a uniaxially stretched two-layer film obtained by the following method was used instead of the uniaxially stretched three-layer film. Production of uniaxially stretched two-layer film Melt flow rate (MFR) 0.8 g / 10 min,
Composition (A) comprising 75 parts by weight of a propylene homopolymer having a crystallinity of 67% and a melting point of 167 ° C., 5 parts by weight of a high-density polyethylene having a melting point of 134 ° C., and 20 parts by weight of calcium carbonate having an average particle size of 1.5 μm. Was melt-kneaded in an extruder set at 250 ° C. and supplied to a co-extrusion die for the base material layer (A).

Another extruder set at 250 ° C. has an MFR of 10 g / 10 min, a crystallinity of 64%, and a melting point of 1
52 parts by weight of a propylene homopolymer at 67 ° C., 45 parts by weight of calcium carbonate having an average particle size of 1.5 μm, and titanium oxide 3
The composition (B), which is blended with the composition (B), is melt-kneaded at 240 ° C., supplied to a co-extrusion die, and laminated on one surface of the composition for the base material layer (A) in the die. And cooled to 60 ° C. with a cooling roll to obtain a non-stretched sheet having a two-layer structure (B / A).

Next, the unstretched sheet having the two-layer structure is
The film is stretched 5 times in the machine direction by a longitudinal stretching machine composed of rolls having different peripheral speeds set at 35 ° C., then annealed at a temperature of 150 ° C., cooled to a temperature of 50 ° C. Slit to 80 μm (B / A = 7 / 73μ
m) A uniaxially stretched bilayer film (B / A) having fine independent voids was obtained. This uniaxially stretched two-layer film is
The void ratio is 23%, the opacity is 80%, and the tensile modulus is 29,600 kgf / c in the stretching direction (longitudinal direction).
m ² , 11,300 kgf / cm ^{2 in the} transverse direction, and the Emmendorf tear strength in the tear direction was 10 g.

[0027]

[Table 1]

[0028]

As described above, it is possible to provide a tying string which is excellent in water resistance and excellent in tearing property of each piece.

[Brief description of the drawings]

FIG. 1 is a front view showing a binding string group according to the present invention.

FIG. 2 is a cross-sectional view of the strap of the present invention.

FIG. 3 is a perspective view showing a binding string group made of a conventional non-stretched film.

FIG. 4 is a perspective view showing a conventional binding strap.

FIG. 5 is a schematic diagram of spinach tied using the tying string of the present invention.

Claims (1)

[Claims] 1. A crystalline polyolefin (A ₁ ) 70 to 9
On at least one surface of 9% by weight and inorganic fine powder core layer of (A ₂₎ a resin composition containing a 30 to 1% by weight as a base (A),. 35 to the inorganic fine powder (B ₂₎ 60% by weight
And a crystalline polyolefin (B ₁₎ 65~40 wt%
The laminated film on which the surface layer (B) made of the resin composition containing is laminated is coated with a crystalline polyolefin (A ₁ , B
The opacity (JIS Z-872) of a uniaxially stretched laminated film obtained by stretching three to ten times in the uniaxial direction at a temperature lower than the melting point of ₁ ) to form many independent fine voids in each layer.
2) is 70% or more, and the product name, barcode, manufacturer, etc. are printed on the surface of the surface layer (B) of the uniaxially stretched multilayer film having an Elmendorf stretching strength (JIS K-7128) of 5 to 15 g in the stretching direction. And a tie strap having a pressure-sensitive adhesive layer provided on the back surface of the uniaxially stretched multilayer film on the side opposite to the printing surface.