JPH0557299B2 - - Google Patents

Description

[Detailed description of the invention]

B. Field of Industrial Application The present invention relates to a tear sheet for transporting containers. More specifically, it mainly contains a blend of propylene homopolymer or propylene-ethylene block copolymer with MFI of 0.1 to 10 g/10 min and 5 to 40% by weight (based on said polymer) of inorganic filler. This relates to a heat-resistant tear sheet consisting of a sheet-like material with a friction coefficient of one side larger than that of the other side and a thickness of 0.3 to 15 mm. It is highly durable, washable, and hygienic, and not only can withstand repeated use, but also has a dustproof effect on unfilled containers, and can facilitate stacking of containers and improve work efficiency. This concerns the tear sheet. B. Conventional technology In recent years, metal containers used for soft drinks, beer, edible oil, canned goods, etc., glass containers used for pharmaceuticals, industrial chemicals, liquid seasonings, etc., liquid detergents, seasonings, ice cream, etc. Large quantities of various containers, such as plastic containers, are used in many fields, and most of the cargo handling work such as packaging and transporting these containers has been automated. One aspect of the above-mentioned packaging and transportation is unit load. This method is a method in which when handling and transporting containers, etc., they are grouped into a suitable number or weight as a unit, and are handled integrally by equipment without being dismantled on the way. In other words, a certain number of containers are arranged in multiple rows on a pallet.
After being stacked in multiple stages to form a unit, it is packed using shrink wrapping or banding, and then used for cargo handling operations. When containers are stacked in multiple tiers to form a unit, a tear sheet is inserted into each tier for the purpose of stabilizing the containers, preventing them from collapsing, and preventing dust. Traditionally, paper boards have been used as tear sheets, but not only are they impossible to clean and cannot be used repeatedly, but paper fiber waste cannot be avoided when transporting unfilled containers, which can cause problems later on. There are concerns that. Also, since the material is paper,
It is unhygienic as it is prone to fluffing, damage, and contamination, and its use is restricted in fields where dust is averse, such as food and medicine. On the other hand, as a plastic tear sheet, a sheet made of a random copolymer of 2 to 10% ethylene and 90 to 98% propylene has been proposed (International Publication No. WO82/01861). however,
When this tear sheet is subjected to high-temperature sterilization in a unit load state for repeated use after washing, the tear sheet not only bends and deforms, but also has to be wrapped in a band and shrink wrapped under heat. There are problems such as bending of the corner portion of the edge. C. Problems to be Solved by the Invention The present invention solves the problems in the prior art as described above. In other words, it has no heat resistance or water resistance, and cannot be sterilized at high temperatures or cleaned.
This is an attempt to solve problems such as easy breakage, easy contamination, and easy generation of fiber waste. Therefore, the present invention has high heat resistance and water resistance,
Not only is it washable and hygienic and can withstand repeated use, but it also has a dust-proofing effect on unfilled containers.
Moreover, the present invention provides a heat-resistant tear sheet that facilitates stacking of containers, improves work efficiency, and does not cause bending or deformation during shrink packaging or stacked storage. D. Means for solving the problems The heat-resistant tear sheet of the present invention has an MFI of 0.1 to
10 g/min of propylene homopolymer or propylene-ethylene block copolymer and inorganic filler 5~
40% by weight (based on the polymer), the entire or desired portion of at least one side is roughened, and the coefficient of friction on one side is greater than the coefficient of friction on the other side. , thickness is 0.3
It consists of a sheet-like material with a diameter of ~15 mm. As the resin component of the heat-resistant tear sheet of the present invention, a propylene homopolymer and a propylene-ethylene block copolymer containing 3 to 25 mol % of ethylene units are used because of their heat resistance. The MFI (melt flow index) of the propylene polymer is in the range of 0.1 to 10 g/10 minutes.
If the MFI is less than 0.1 g/10 minutes, the fluidity of the molten resin will be poor and the load on the screw of the extruder will become too high, making it difficult to produce a good sheet. on the other hand,
If the MFI exceeds 10 g/10 minutes, the molten resin web will sag and good molding will not be possible. Moreover, the strength and other physical properties of the sheet become inferior. If necessary, the above polymers may be added to synthetic rubber such as styrene-butadione copolymer rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, butyl rubber, chloroprene rubber, natural rubber, etc. It is also possible to mix other elastomers. The inorganic filler used in the present invention has a shape such as a powder, a plate, a scale, a needle, a sphere, a hollow, a fiber, a fiber fabric, etc. Specific examples include carbonate Calcium, magnesium carbonate, calcium sulfate, calcium silicate, barium sulfate, aluminum hydroxide,
Magnesium hydroxide, calcium hydroxide, calcium sulfite, mica, clay, diatomaceous earth, talc,
Zeolite, zinc oxide, titanium oxide, molybdenum sulfide, quartz powder, bentonite, alumina, silica sand,
Iron oxide, metal powder, antimony trioxide, graphite, silicon carbide, silicon nitride, silica, boron nitride,
Powder-like fillers such as aluminum nitride, white carbon, carbon black, glass beads, glass powder, silica stone, mica, glass plates, sericite,
Pyrofilite, aluminum flakes and other metal foils, flat or scaly fillers such as graphite, shirasu balloons, metal balloons, glass balloons,
Hollow fillers such as pumice, fibrous fillers such as glass fiber, whiskers, metal fibers, silicon carbide fibers, carbon fibers, graphite fibers, mineral fibers such as asbestos and wollastonite, and fiber fabrics such as glass fiber pine Examples include shaped fillers. Among these, talc is the most preferable from the comprehensive viewpoint of the tear sheet, such as heat resistance, mechanical properties such as flexural modulus, and workability, and the particle size is 2 to 2.
A range of 10μ is preferred. If the particle size exceeds 10μ, there is a concern that the impact resistance strength will decrease, and if the particle size is less than 2μ, it is preferable in terms of physical properties, but is expensive and economically disadvantageous. The amount of the above-mentioned inorganic filler blended can be appropriately selected within the range of 5 to 40% by weight based on the weight of the propylene polymer. If the amount of inorganic filler added is less than 5% by weight, required physical properties such as heat resistance cannot be satisfied. On the other hand, if it exceeds 40% by weight, there is a concern that mechanical strength will decrease, which is not preferable. The above-mentioned inorganic filler can be blended using a conventional kneading machine such as a single screw extruder, a twin screw extruder, a Banbury mixer, a roll, or a kneader.
Further, when the filler is made of a woven fabric such as glass fiber mat, the woven fabric can be laminated with a propylene polymer in the form of a sandwich. The present invention involves mixing the above-mentioned propylene polymer and inorganic filler in a desired ratio, forming a sheet by a conventional method such as extrusion molding, T-die method, or calendar method, and then embossing the entire or desired portion of at least one side. processing, sandblasting, corona discharge treatment,
By roughening the surface by subjecting it to a surface treatment such as flame treatment or plasma treatment, the coefficient of friction between one side and the other side of the tear sheet can be made different, or by coating the surface of the tear sheet with ethylene-vinyl acetate copolymer, synthetic rubber, etc. By laminating or laminating anti-slip materials, containers can be easily stacked and transported to prevent cargo from slipping or collapsing. The above coefficient of friction varies depending on the type of metal, glass, or plastic container, the shape of the bottom of the container, the weight of the container, etc., but when the roughened surface is used as the front, for example, beer For metal cans such as cans, the coefficient of static friction is suitably in the range of 0.1 to 0.6, preferably 0.2 to 0.5. Furthermore, depending on the type of container, it may be used with the roughened side facing down. Furthermore, the thickness of the heat-resistant tear sheet of the present invention is appropriately selected within the range of 0.3 to 15 mm, preferably 0.5 to 10 mm. When the thickness of the tear sheet is less than 0.3mm,
If the mechanical strength such as rigidity of the sheet is poor and the thickness exceeds 15 mm, the physical properties required by the present invention will be satisfied, but the weight will be large and there is a concern that it will hinder automation and handling of cargo. There is. The shape of the heat-resistant tear sheet of the present invention is rectangular,
It can be any suitable shape such as square, oval, circular, etc.
In the case of a shape with corners, such as a rectangle or square, it is desirable to round each corner to match the shape of the container. In addition, holes for drainage may be formed at desired locations on the tear sheet to the extent that required physical properties such as rigidity are not compromised, or fine irregularities may be applied during sheet forming to adjust the contact area with the container. It is also possible to give directionality when arranging the containers. Furthermore, if an antistatic agent is added, if necessary, the tear sheet prevents the adhesion of dust, so it has a remarkable effect as a tear sheet for unfilled containers. In addition to the above additives, the present invention also includes antioxidants,
There is no problem in adding ordinary additives such as lubricants, ultraviolet absorbers, flame retardants, dispersants, and crosslinking agents. E. Effects As mentioned above, the heat-resistant tear sheet of the present invention is water resistant, so it can withstand repeated use by washing.
Not only is it hygienic, but it also has a dust-proofing effect on unfilled containers, facilitates stacking of containers, improves work efficiency, and has heat resistance that allows for high-temperature sterilization and shrink packaging. . In addition, the heat-resistant tear sheet of the present invention has surface properties (scratch resistance, gloss, flow marks, etc.) as well as printability, depending on the type of inorganic filler added.
Improvements in various properties such as paintability, adhesion, plating, tapping, weld strength, creep resistance, and dimensional stability can be expected. F. EXAMPLES The present invention will be explained in more detail with reference to Examples below. Example 1 Polypropylene homopolymer (MFI1=1.0g/10
5% by weight of talc (product name: PK-C, manufactured by Hayashi Kasei Co., Ltd.)
An extruder (90 mmφ) was used to mix a composition with an average particle size of 10μ, a water content of 0.13%, and a white flake-like composition at a resin temperature of 250°C, a cooling roll temperature of 100°C, and a take-up speed of 5 m/min.
min sheet forming condition, thickness 1.0mm x length 1440mm
A sheet with a width of 1130 mm was molded, and the surface of the sheet was further embossed to obtain a heat-resistant tear sheet. 350ml beer cans are arranged and loaded in 21 vertical rows x 19 horizontal rows on the embossed surface of the tear sheet. Stack these in 14 layers on a plastic pallet, place another tear sheet on top of the top layer of cans, and place a plastic top plate on top of that. This was banded as one unit and shrink-wrapped at 160°C for 45 seconds, and the conditions were observed. The results are shown in Table 1. The physical properties were tested in accordance with the test method below. Item Test method Tensile test ASTM D638 Heat deformation temperature ASTM D648 Flexural modulus ASTM D790 Izot impact strength ASTM D256 (notched, 23°C) The test pieces used in the above tests were made by crushing each tear sheet and injection molding. . Injection molding conditions Injection pressure 1000Kg/cm ² Injection time 15sec. Cooling time 20sec. Mold temperature 50℃ Resin temperature 270℃ Examples 2 to 5 Various talcs were added to the resin used in Example 1. The same test as in Example 1 was carried out by adding the following proportions. The results are shown in Table 1. Example 6 10% by weight of the talc used in Example 1 was added to a propylene-ethylene block copolymer (MFI = 1.5 g/10 min, product name: J724, manufactured by Nippon Petrochemical Co., Ltd.), and the rest was carried out. The same procedure as in Example 1 was carried out. The results are shown in Table 1. Example 7 The same procedure as in Example 1 was carried out except that 30% by weight of the talc used in Example 1 was added to the propylene-ethylene block copolymer of Example 6. The results are shown in Table 1. Comparative Example 1 Only the resin used in Example 1 was formed into a sheet in the same manner as in Example 1, and the same test was conducted.
The results are shown in Table 1. Comparative Example 2 Only the resin used in Example 6 was formed into a sheet in the same manner as in Example 1, and a test was conducted. The results are shown in Table 1. Comparative Example 3 The same procedure as in Example 1 was carried out except that 45% by weight of the talc used in Example 1, which is outside the scope of the present invention, was added to the resin used in Example 1. The results are shown in Table 1. As a result of adding a large amount of talc, the heat resistance improved, but the elongation and Izot impact strength were low and the product was brittle. Comparative Example 4 A propylene-ethylene random copolymer (MFI = 0.5 g/10 minutes, manufactured by Nippon Petrochemical Co., Ltd.) was formed into a sheet in the same manner as in Example 1, and the same test was conducted. The results are shown in Table 1. Comparative Example 5 40% by weight of the talc used in Example 1 was added to the propylene-ethylene random copolymer used in Comparative Example 4.
The other procedures were the same as in Example 1. The results are shown in Table 1.

[Table] The edge part is deformed into a corrugated plate shape.
G. Effects of the Invention As can be seen from the above description and examples, the heat-resistant tear sheet of the present invention has high rigidity and high heat-resistant strength, and also has good impact resistance. In addition, since it is made of plastic material, it is highly water resistant, washable, and hygienic, can withstand repeated use, does not contaminate the container, and can be sterilized at high temperatures. It has many features such as not bending or deforming at times.

Claims (1)

[Claims] 1. A blend of a propylene homopolymer or a propylene-ethylene block copolymer with an MFI of 0.1 to 10 g/10 minutes and an inorganic filler of 5 to 40% by weight (based on the above polymer). 1. A heat-resistant tear sheet consisting mainly of a composition containing a composition, having a roughened surface on the entire or desired portion of at least one side, having a coefficient of friction on one side larger than that on the other side, and having a thickness of 0.3 to 15 mm. 2. The heat-resistant tear sheet according to claim 1, wherein the inorganic filler is talc.