JP3290755B2 - Spacer sheet for beverage containers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spacer sheet for beverage containers, and more particularly to a container for storing and transporting containers such as aluminum cans and steel cans for beverages such as beer and juice in several stages. And a spacer sheet suitable for use as a spacer between the top and bottom of the spacer sheet.

[0002]

2. Description of the Related Art When a beverage container is stored and transported, a spacer sheet 1 is usually placed on a large number of arranged beverage containers 2 as shown in FIG. In addition, a method is employed in which a large number of containers are further arranged and stacked in several or tens of layers. The spacer sheet is made of cardboard made of pulp fiber and has a high surface smoothness.The stacking of the containers is performed by using a machine to slide the containers on the surface of the spacer sheet and then arranging the containers. Is further placed on the spacer sheet, and the containers are similarly slid and lined up.

[0003] When the spacer sheet is repeatedly used, cleaning is usually performed by a sterilization step using ultraviolet rays. However, when cardboard is used as the spacer sheet, dust and the like are apt to be generated, and such dust cannot be removed in the sterilization process. Not preferred. Therefore, it is necessary to remove dust and the like by washing the spacer sheet with water or the like. However, since the surface of the cardboard is weak to water and wet friction, there is a problem that it cannot be used repeatedly several times. To solve this problem, a method of using a plastic plate instead of cardboard is conceivable.However, the plastic plate surface is damaged in the process of sliding and juxtaposing containers, resulting in reduced slipperiness and repeated use. You can't do that. In addition, when a plastic foam having flexibility is used, the surface is hardly damaged, but there is a drawback that sufficient slipperiness cannot be obtained.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a spacer sheet for a beverage container which has good sliding properties, abrasion resistance and washing resistance, and can be used repeatedly. Is to provide.

[0005]

The present inventors have focused on a polyolefin sheet having water repellency, that is, a polyolefin nonwoven fabric and an oriented film, and studied the slipperiness of the surface. Headings,
It has been found that by setting the sheet surface roughness to 0.4 to 1.8 and setting the coefficient of static friction to a predetermined value or less, good slipperiness can be obtained, and arrived at the present invention. The present invention relates to a spacer sheet for a beverage container, wherein a polyolefin sheet having a surface roughness of 0.4 to 1.8 is adhered to at least one surface of a resin flat plate. In addition, the said surface roughness value means the SMD value measured with the KES surface tester.

The polyolefin sheet used in the present invention has a surface roughness of 0.4 to 1.8, preferably 0.5 to 1.8.
There is no particular limitation as long as it is within the range of 1.4, but specifically,
Polyolefin nonwoven fabric manufactured by flash spinning method,
An oriented polyolefin film stretched in at least one axis direction is exemplified. Further at least one surface is antistatic processing of these nonwoven or film, and the water pressure resistance is what is preferable 300mmH ₂ O or more. When the surface roughness of the polyolefin sheet is out of the range of 0.4 to 1.8, the static friction coefficient (μ) of the spacer sheet is 0.1.
When it is 40 or more, the slipperiness of the spacer sheet cannot be secured, and when arranging the containers, the containers not only do not move smoothly, but also easily fall down.

In the present invention, the polyolefin sheet has a moderate cushioning property on the sheet surface,
That is, it is preferable to use a nonwoven fabric having an appropriate gap because frictional scratches caused by the movement of the container hardly enter the topsheet. As the polyolefin nonwoven fabric, it is preferable that the surface is composed of ultrafine fibers, and it is preferable that the nonwoven fabric has a smooth surface in terms of surface slippage and washing resistance. Specifically, a polyolefin nonwoven fabric formed by a flash spinning method is preferable. As the flash spinning method, for example, an example of a method for producing high-density polyethylene disclosed in JP-B-62-172773, an example of a method for producing polypropylene disclosed in JP-B-62-192598, and the like can be employed.

An example of the flash spinning method will be described below. First, a polyolefin polymer is dissolved under high temperature and high pressure with a halogenated carbon such as trichlorofluoromethane and trichlorotrifluoroethane, a hydrocarbon such as methylene chloride, or a mixture thereof, and then a sharp pressure loss is applied to the solution to make the solution extremely. Gives a structure as if finely phase separated. The liquid is discharged from a spinning nozzle to give orientation to the polymer and to form a three-dimensional network fiber. This is shaken down on a conveyor belt to form a web, and then partially or wholly pressed by a roll such as a smooth roll or an emboss roll or a felt calender maintained at a normal temperature or an appropriate temperature (the melting point of the polyolefin or lower) to form a sheet. I do. This nonwoven fabric consists of fibers having a very fine and complex cross-sectional structure. In addition, it is preferable to set the porosity to 40 to 80% at the time of press bonding from the viewpoint of cushioning property and abrasion of the container so that scratches are hardly caused. The nonwoven fabric thus obtained has a surface roughness in the range of 0.4 to 1.8.

In the present invention, a nonwoven fabric other than the flash spinning method may be used. In this case, surface smoothness is imparted by a known film forming process such as calendering, and surface roughness is reduced to 0.4 by suppressing surface fuzz.
８1.8. The basis weight of the polyolefin nonwoven fabric is usually 20 to 200 g / m ² , preferably 40 to 100 g / m ² . If the basis weight is less than 20 g / m ^2, it is difficult to obtain sufficient slipperiness due to unevenness in the basis weight,
Further, the container is apt to be broken by abrasion, which is not preferable. If it is more than 200 g / m ² , flexibility is impaired, and wrinkles or breaks are apt to occur during production, which is not preferable in terms of quality.

Since the polyolefin nonwoven fabric has poor antistatic properties and tends to be dusty, it is subjected to an antistatic process on at least one side to impart antistatic properties and has a water pressure of 300 mmH ₂ O or more for improving water washing resistance. Is preferred. As the antistatic agent, a hexyl phosphate salt, a methoxyalkyl phosphate salt, an alkylalkylene oxide phosphate salt, an oxacycloalkylmethyl phosphate salt, or the like is preferably used. An appropriate amount of the antistatic agent or the water repellent is determined depending on the type of the antistatic agent or the water repellent, the molecular structure of the nonwoven fabric, the surface state, and the like. The application of the antistatic agent can be performed by a known method such as a dip-nip method, a coating method, a gravure roll method, a kiss roll method, and a spray method. Further, it is possible to perform the water repellent treatment simultaneously with the antistatic treatment. For example, the amount of methoxybutyl phosphate potassium deposited on the polyethylene nonwoven fabric by the above-mentioned flash spinning method is 0.5 to 10% based on the dry sample weight.
By weight percent adhesion, the water repellency is 80 or more, the water resistance is 500 mmH ₂ O or more, and the surface resistance is 1 × 1
Or less 0 ⁹ Omega antistatic and can be produced a nonwoven fabric having a waterproof.

In the present invention, an oriented film stretched in at least one axial direction can be used as the polyolefin sheet. Examples of the oriented film made of a polyolefin resin include, for example, Japanese Patent Publication No. 4-7
No. 4,373,437.
By containing a suitable inorganic fine powder in the production process of the oriented film, the surface roughness of the film is 0.4 to
It can be in the range of 1.8. The oriented film can be subjected to antistatic treatment, water-repellent treatment, calendering, and the like in the same manner as the nonwoven fabric described above.

Examples of the resin flat plate used in the present invention include a plate-shaped plastic sheet made of a polyolefin resin, an acrylic resin, a polyester resin, a vinyl chloride resin, a polyamide resin, or the like. Of these,
It is preferable that the material is the same as the polyolefin sheet from the viewpoint of recycling and waterproofness. The plate-like plastic sheet may be a foam. The porosity is preferably 85% or less from the viewpoint of easiness of scratching and prevention of a decrease in slipperiness, and the form of foam is preferably a closed foam from the viewpoint of shape recovery force.

Since it is required that the flat resin plate does not easily bend under the weight of the container or its own weight and that the end of the flat plate is not easily bent, the basis weight is usually 100 g / m ^2.
That is all. In addition, it is not preferable at 1000 g / m ² or more in terms of workability and cost. The surface roughness of the resin flat plate does not need to have large unevenness because the polyolefin sheet is adhered to at least one surface, and does not need to be strictly flat and smooth. There is no particular limitation on the method of bonding the resin flat plate and the polyolefin sheet, and for example, a method of extruding and bonding a molten resin onto the polyolefin sheet, a thermocompression bonding method, a heat sealing method, an ultrasonic bonding method, or the like is adopted. can do. The coefficient of static friction of the spacer sheet is usually 0.40 or less, preferably 0.35 or less.
It is as follows.

[0014]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the invention thereto. In addition,
The properties of the spacer sheet for beverage containers and the polyolefin sheet were measured by the methods described below. (1) Surface roughness (SMD) A sample of 20 cm x 20 cm is cut out from a base material. A KES-FB4 surface tester (with an automatic calculation function) manufactured by Kato Tech Co., Ltd. is used as the tester. 400
Then, the device is started by applying a load of 10 g and bringing the contact for surface roughness detection with a load of 10 g into contact with the sample. Each process of the sample is measured three times, and the average thereof is defined as the surface roughness. (2) Static friction coefficient Measurement is performed according to JIS-P-8147. Using a static friction coefficient measuring device (TYPE HEIDON-10), the sample was fixed on a tilting table, and an aluminum can (Asahi Super Dry 350ml 92.10 manufactured product) was placed on the sample, tilted, and started to slide. The static friction coefficient is determined from the angle obtained, the details are measured three times, and the average thereof is defined as the static friction coefficient.

(3) Abrasion strength A test piece of 15 cm × 15 cm was taken, and a Gakushin type friction tester (JI
Using SL-0823), the sample was fixed on a sample table of a Gakushin-type testing machine with a gum tape, and then an aluminum can (Asahi Super Dry 350 ml) was cut into about 1/3, and the bottom of the aluminum can was fitted with a friction element. Fix to the tip so that it does not move, and apply a load of 500
g at a speed of reciprocating 30 times per minute between 10 cm of test pieces.
After reciprocating and reciprocating 50 times, the appearance change and static friction coefficient of the test piece are measured. The change in appearance of the test piece is visually judged according to the following criteria. Class A: No scratches and no fluff. Class B: Some scratches. Somewhat fuzzy. Class C: Scratches are noticeable. Fuzz is noticeable. (4) Antistatic property (surface resistance measurement method) A voltage of 500 V is applied to the protective electrode from the main electrode placed on the sample surface, and the surface electrical resistivity is determined from the current flowing through the protective electrode (JIS-L- 1094 surface leakage resistance measurement Main electrode diameter: 50 mm Protection electrode inner diameter: 70 mm).

(5) Dusting test According to JIS-L-1094 frictional voltage measuring method, 20
After charging the test piece with a rotary static meter (400 rpm, 1 minute) in a constant temperature chamber at 40 ° C. and 40% RH, sprinkle with a carbon toner, lightly knock the sample off, and perform visual judgment according to the following criteria. Class A: No dust. Class B: Slightly dusty. Class C: Extremely dusty. (6) Resistance to Water Washing A test piece was cut into a size of 20 cm × 20 cm, and the surface of the sample was stained with a carbon toner. Then, the sample was wiped off with water using a 100% cotton cloth until the stain became inconspicuous, and dried at 80 ° C. This is repeated three times, and the visual judgment is made based on the following criteria. Class A: No scratches and no fluff. Class B: Some scratches. Somewhat fuzzy. Class C: Scratches are noticeable. Fuzz is noticeable.

(7) Water pressure resistance test Water resistance test for textiles (JIS-L-1092) Measured by the hydrostatic pressure of Method A and Method B. (8) Basis weight and thickness Measure according to JIS-L-1096 method. However, the load for measuring the thickness is 100 g / cm ² . (9) Porosity (%) It is calculated from the measured values of the basis weight and the thickness by the following method. Porosity (%) = ｛1-[weight (g / m ² ) / (thickness (m) × specific gravity (g / m
³ )))｝ × 100

The polyolefin sheets (A) to (F) and (a) used in Examples 1 to 6 and Comparative Examples 1 to 6
(d) was prepared by the following methods. (1) Polyethylene non-woven fabric (A) A solvent composed of high-density polyethylene polymer (MI = 0.8) and Freon 11 is discharged from a nozzle from a high-temperature high-pressure condition to a low-temperature low-pressure region to flush the solvent and deposit it in a wire mesh form. After the fibrillated reticulated fiber was formed, it was treated on both sides with a felt calender. High-speed treatment was performed with contact with the drum heated to 132 ° C. for 1 second to obtain a polyethylene nonwoven fabric (A) having a surface layer thermocompressed and having a basis weight of 62 g / m ² , a thickness of 0.20 mm and a porosity of 67%. Was. Surface roughness of non-woven fabric (SM
D) was 1.2.

(2) Polypropylene nonwoven fabric (B) Polypropylene polymer (MI = 1.0) and Freon 11
The solvent consisting of is discharged from the nozzle from the high-temperature high-pressure condition to the low-temperature low-pressure area to flush the solvent and deposit it in a wire mesh,
After the fibrillated reticulated fiber was formed, it was treated on both sides with a felt calender. 1 contact with the drum heated to 160 ° C
Seconds, processed at high speed and the surface layer was thermo-compressed.
A polypropylene nonwoven fabric (B) having 0 g / m ² , a thickness of 0.25 mm, and a porosity of 71% was obtained. Surface roughness of nonwoven fabric (SMD)
Was 1.4. (3) Polypropylene non-woven fabric (C) Using a rectangular spinneret having a hole diameter of 0.25 mm and a number of holes of 1,000, spinning speed of 850 g / min at a melting temperature of 190 ° C. at a melting temperature of 190 ° C. and air soccer of 5000 m.
/ Min. To form a web with a basis weight of 100 g / m ² . Using a pair of smooth rolls, the web was set to a temperature of 155 ° C. for the upper metal roll and a temperature of 80 ° C. for the lower paper roll, and subjected to thermocompression bonding at a linear pressure of 70 kg / cm on both sides to a thickness of 0.18 mm and a gap. 43% polypropylene nonwoven fabric (C)
I got The surface roughness (SMD) of the nonwoven fabric was 0.9.

(4) Polyethylene non-woven fabric (D) The polyethylene non-woven fabric (A) obtained in (1) was set at a temperature of 50 ° C. for the upper metal roll and 30 ° C. for the lower paper roll using a pair of smooth rolls. , Linear pressure 70kg / cm
Thermocompression bonding on both sides, thickness 0.17mm, porosity 61%
Thus, a polyethylene nonwoven fabric (D) was obtained. The surface roughness (SMD) of the nonwoven fabric was 0.6. (5) Polyethylene non-woven fabric (E) After subjecting one side of the polyethylene non-woven fabric (A) obtained in (1) to a corona treatment, potassium 3-methoxybutyl phosphate was added at 1.0% by weight based on the dry weight of the non-woven fabric. Is applied by a spray method so that the surface resistance value is 3 × 10 ⁹ ,
A polyethylene nonwoven fabric (E) having a water resistance of 520 mmH ₂ O was obtained.

(6) Oriented polypropylene film (F) Polypropylene (MI = 0.8) is mixed with 20% by weight of calcium carbonate having an average particle size of 1.8 μm (based on the total weight with polypropylene) and set at 270 ° C. After kneading with an extruder, the mixture was extruded into a sheet, cooled, heated to 140 ° C., stretched 5 times in the longitudinal direction, and weighed 116 g / m ² , having a thickness of 0.15 mm and having a porosity of 25%. F). The surface roughness (SMD) of the film is 0.
It was 5.

(7) Polyethylene non-woven fabric (a) A solvent consisting of high-density polyethylene polymer (MI = 0.8) and chlorofluorocarbon 11 is discharged from a nozzle from a high-temperature high-pressure condition to a low-temperature low-pressure region to flush the solvent to form a metal mesh. After being deposited to obtain fibrillated reticulated fibers, both sides were treated with a felt calender. The contact with the drum heated to 120 ° C. was performed at a high speed by setting the contact time to 1 second to obtain a polyethylene nonwoven fabric (a) having a basis weight of 60 g / m ² , a thickness of 0.23 mm, and a porosity of 72%. The surface roughness (SMD) of the nonwoven fabric was 2.1. (8) Polypropylene non-woven fabric (b) Using a rectangular spinneret having a hole diameter of 0.25 mm and a number of holes of 1,000, spinning speed of 850 g / min at a melting temperature of 190 ° C. at a melting temperature of 190 ° C., and air soccer of 5000 m.
/ Min. To form a web with a basis weight of 100 g / m ² . Using a pair of embossing rolls, the web was heated at a temperature of 165 ° C. of the upper metal embossing roll and at a temperature of 2
Set to 2 ° C, thermocompression bonded to both sides at a linear pressure of 70 kg / cm,
0.18mm thick, 43% porosity non-woven polypropylene fabric
(b) was obtained. The surface roughness (SMD) of the nonwoven fabric was 2.4.

(9) Polypropylene non-woven fabric (c) The polypropylene non-woven fabric (B) obtained in (2) is heated at a temperature of 130 ° C. of an upper metal roll using a pair of smooth rolls.
Set the lower paper roll temperature to 60 ° C and set the linear pressure to 150 ° C.
Thermocompression bonding was performed on both sides at kg / cm to obtain a polypropylene nonwoven fabric (c) having a thickness of 0.10 mm and a porosity of 38%. The surface roughness (SMD) of the nonwoven fabric was 0.3. (10) Polypropylene oriented film (d) Polypropylene (MI = 0.8) is mixed with 10% by weight of calcium carbonate having an average particle size of 1.8 μm (based on the total weight with polypropylene) and set at 270 ° C. After extruding into a sheet, the mixture was cooled, heated to 140 ° C., and stretched 5 times in the machine direction to obtain a polypropylene oriented film (d) having a basis weight of 109 g / m ² , a thickness of 0.13 mm and a porosity of 18%. Obtained. The surface roughness (SMD) of the film is 0.
It was 2.

Examples 1 to 5 and Comparative Examples 1 to 5 Resins
As a flat plate, extruded basis weight 480 g / m^Two, Thickness
Use a 0.5mm polypropylene plate and place one side
(A), (B), (C), (D)
 , (F) and (a), (b), (c), (d)
This produced a spacer sheet. The method of bonding is
Glue (Henkel white)
X-3520) (manufactured by Suisha Co., Ltd.) at 10
g / m ^TwoAnd bubbles remain between the plate and the polypropylene plate.
And dried at 80 ° C. Comparative Example 5
A polypropylene plate to which the sheet was not adhered was used. Profit
Spacer sheet and polypropylene plate
The coefficient of static friction (μ), abrasion strength and washing resistance
The results are shown in Table 1. Table 1 shows that the present invention
The spacer sheet has excellent slip and abrasion resistance,
It can be used several times because of its excellent washing resistance.
Is shown.

[0025]

[Table 1]

Example 6 and Comparative Example 6 An extruded basis weight of 200 g / m ² and a thickness of 1.0 as a resin flat plate.
A polyolefin sheet (E) was adhered to both sides of a polyethylene closed-cell foamed plate (trade name: Softlon manufactured by Sekisui Chemical Co., Ltd., porosity: 80%) to prepare a spacer sheet. The bonding was performed by placing a polyolefin sheet on a resin flat plate and thermocompression bonding at 120 ° C. As Comparative Example 6, a polyethylene independent foam plate to which no sheet was bonded was used. The obtained spacer sheet and polyethylene independent foam board were examined for a coefficient of static friction (μ), abrasion strength, resistance to washing with water and a dusting test, and the results are shown in Table 2.
Table 2 shows that the spacer sheet of Example 6 has excellent slipperiness and abrasion resistance, can be used several times, and is hardly soiled and hardly dusted.

[0027]

[Table 2]

[0028]

The spacer sheet for a beverage container according to the present invention has a polyolefin sheet having a specific surface roughness on the surface of a resin flat plate, so that the spacer sheet has good sliding properties, is resistant to abrasion, and can be washed with water. Several orders that were not possible are possible. In particular, by using a nonwoven fabric produced by a flash spinning method or an oriented film stretched in at least one axis direction as the polyolefin sheet, the surface slippage and abrasion resistance are further improved. Further, by subjecting the polyolefin sheet to an antistatic treatment and a water-repellent treatment, dust and the like are less likely to be attached, and the washing resistance is improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a method of storing and transporting a beverage container.

[Explanation of symbols]

 1. spacer sheet, 2. beverage container.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B65D 71/00 B32B 1/00-35/00

Claims (4)

(57) [Claims] 1. A spacer sheet for a beverage container, wherein a polyolefin sheet having a surface roughness of 0.4 to 1.8 is adhered to at least one surface of a resin flat plate. ^2. The spacer sheet for a beverage container according to claim 1, wherein the polyolefin sheet is made of a nonwoven fabric having a basis weight of 20 to 200 g / m ² manufactured by a flash spinning method. 3. The spacer sheet for a beverage container according to claim 1, wherein the polyolefin sheet is an oriented polyolefin film stretched in at least one axial direction. 4. The spacer sheet for beverage containers according to claim 1, wherein at least one surface of the polyolefin sheet is subjected to antistatic processing and has a water pressure resistance of 300 mmH ₂ O or more.