JPS6127181B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to anti-slip polyolefin molded articles. Specifically, the present invention relates to a polyolefin molded product equipped with an anti-slip material that has an excellent anti-slip effect and good durability. Polyolefin molded products have come to be widely used in place of wood, metal, etc. because they have excellent water resistance, chemical resistance, etc., are hygienic, and have consistent molded product specifications. However, although this polyolefin molded product has the above-mentioned excellent features, it also has the drawback of being slippery. Particularly when pallets used for transporting or storing cargo are made from polyolefin molded products, slipping may occur between the cargo and the pallet, between the pallet and fork such as a forklift, or between pallets. There is a risk of the cargo collapsing when transporting or transferring the cargo. Conventionally, methods to prevent the above-mentioned slipping have been used, such as creating irregularities on the surface of molded products such as pallets, or fitting rubber anti-slip fittings, but these methods have various problems. It's hard to say that I'm still satisfied with it. The inventors of the present invention have conducted extensive studies in order to eliminate the drawback of the slipperiness of conventional polyolefin molded products as described above, and as a result, they have developed a method for attaching an anti-slip material made of a special composition to a polyolefin molded product in a specific configuration. They discovered that the problem could be solved by doing this and completed the present invention. That is, the gist of the present invention is to provide a non-slip polyolefin molded product in which a non-slip material is thermally welded to a polyolefin molded product, in which the non-slip material is composed of 20 to 80% by weight of ethylene propylene rubber and 80 to 20% by weight of linear low-density polyethylene. % by weight, and the ethylene propylene rubber contains 60 to 80% by weight of an ethylene component and 40 to 20% by weight of a propylene component. exists in An example of the molded product of the present invention will be further explained below with reference to the drawings. FIG. 1 is a perspective view of a pallet which is an example of the molded product of the present invention. In the figure, 1 indicates a molded product (pallet), and 2 indicates a non-slip material. The synthetic resin constituting the molded product (pallet) 1 of the present invention is selected from consideration of thermal weldability with the anti-slip material 2, etc.
Polypropylene, polyethylene, polybutene
1. Ethylene-propylene copolymer, ethylene-
Polyolefin resins such as vinyl acetate copolymers are used, and among them, those with hardness (hardness according to JIS K6301) of JIS A97 or higher and close to 100 are preferred.
To put this more simply, the shore hardness (hardness according to ASTM D2240 shore D) is 60 or more,
Preferably, a hard polyolefin whose main component is polypropylene or polyethylene having a molecular weight of 70 or more is preferred. Additions of antioxidants, ultraviolet absorbers, heat stabilizers, antistatic agents, flame retardants, crosslinking agents, foaming agents, dye pigments, organic fillers, inorganic fillers, etc. are added to the polyolefin constituting the molded product 1 described above. The agent may be added and mixed, and the molded product 1 may be molded by injection molding,
Conventional molding methods such as extrusion molding and cast molding can be used as desired depending on the desired molded product. When the molded product 1 is a pallet, it is desirable to add a foaming agent to the above-mentioned polyolefin to obtain a low-foaming injection molded product having a non-foamed layer on the surface layer at an expansion ratio of about 1.05 to 1.5 times. Of course, it may be non-foamed. The anti-slip material 2 is obtained by molding a blend of ethylene propylene rubber and linear low density polyethylene. Ethylene propylene rubber is a rubber-like product obtained by polymerizing, for example, ethylene and propylene in the presence of a Ziegler catalyst. This ethylene propylene rubber has an ethylene component of 60 to 80% by weight, preferably 70 to 80% by weight.
80% by weight, and a propylene component of 40 to 20% by weight, preferably 30 to 20% by weight. Furthermore, linear low-density polyethylene is a copolymer of ethylene and other α-olefins, and is different from low-density polyethylene resin produced by conventional high-pressure methods. Linear low-density polyethylene can be produced by a gas phase method or a liquid phase method using, for example, 1 to 20% by weight, preferably 3 to 7% by weight of ethylene and other α-olefins such as butene, hexene, octene, decene, etc. to produce 100 kg. /cm ² or less, preferably 60Kg/cm ² or less. This linear low-density polyethylene is made from conventional high-density polyethylene with a copolymerization component that has a short branching structure, and the density is appropriately lowered by utilizing the short chain branching to 0.91 to 0.95 g/
cm ² and has a more linear structure than conventional low-density polyethylene and more branched than high-density polyethylene. The anti-slip material 2 is made of a mixture of ethylene propylene rubber and linear low density polyethylene as described above, and the blending ratio is 20 to 80% by weight of ethylene propylene rubber, preferably 30 to 70% by weight, more preferably 40% by weight. -60% by weight, linear low density polyethylene 80-20% by weight, preferably 70-30% by weight, more preferably 60-40% by weight. Of course, the above-mentioned additives may be further added to this mixture. Further, in addition to the above-mentioned ethylene propylene rubber and linear low-density polyethylene, other thermoplastic synthetic resins may be added to these mixtures in an amount not exceeding the amount of each of the above two components. As other thermoplastic synthetic resins, polyolefin resins are preferred, and among them, ethylene-vinyl acetate copolymer is preferred. Furthermore, a part of the above ethylene propylene rubber may be mixed with ethylene propylene diene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, polybutadiene rubber, polyisoprene rubber, within a range not exceeding the blended amount of ethylene propylene.
Other synthetic rubbers such as polychloroprene rubber, polyurethane rubber, and thiol rubber may be used instead. The anti-slip material 2 is made of the above-mentioned mixture and is molded into a desired shape such as a band, string, or block by an appropriate molding method such as extrusion molding or injection molding. The anti-slip material 2 should have a hardness (according to JIS K6301) of JIS A75 to JIS A95 and a tensile strength {JIS
Strength of K6758-81 (at constant temperature of 20℃)} is 50
-250Kg/cm ² is desirable. Heat welding is used to install the anti-slip material 2 on the molded product 1. For example, if the surface of the molded product 1 and the surface of the non-slip material 2 are melted using hot air or a hot plate, both of them are still molten. Crimp while in the state,
A method of joining the two, when molding the molded product 1 by injection molding etc., the anti-slip material 2 is placed at the required position in the mold.
A method of fixing the polyolefin in a mold, filling the mold with molten polyolefin, and using the heat of fusion to thermally weld the molded product 1 and the anti-slip material 2. , a method is used in which the material is extruded into a string shape or the like, and then pressed and welded to the surface of the molded product 1 (which may be preheated, oxidized, etc., to improve adhesion). Usually, a method is used in which a non-slip material 2 is placed near a molded product 1, and hot air is blown onto both to melt the surface of the molded product 1 and the surface of the non-slip material 2, and the two are crimped and welded. It will be done. The welding conditions for this welding method vary depending on the temperature of the hot air, the volume of the hot air, the distance from the hot air outlet to the molded product 1 and the anti-slip material 2, etc., and cannot be determined unconditionally, but the line speed is approximately 1 m/min. As an example, hot air of about 600 to 800°C (temperature of the heater in the hot air generator) is blown onto the surface of the molded product 1 and the surface of the anti-slip material 2. Form a molten layer, and while both surfaces are in a molten state, separate the molten parts from each other.
This is done by pressing with a pressure roller or the like at a pressure of about 0.5 kg/cm or more. Next, the characteristics of the molded article of the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. Various physical properties described in the examples were measured by the following measurement methods. (1) Melt index: Measured at a constant temperature of 20°C in accordance with JIS K6760-81. (2) Density: Same as above (3) Tensile strength: Same as above (4) Elongation: Same as above (5) 180° peel strength: Length of non-slip material with width of 20 mm and thickness of 2 mm welded to the base material Using a test piece of approximately 250 mm, peel approximately half of the anti-slip material from the base material in the length direction of the anti-slip material, and test one end of the non-slip material and base material with the peeled anti-slip material folded back 180 degrees. Fix it to the chuck of the machine and keep it at 20℃.
The anti-slip material was peeled off from the base material at a constant temperature of 50 mm/min, the force required for peeling was read, and the average value was expressed in kg/cm. (6) Sliding angle: 2mm thick, length and width on the surface plate
Install a 250mm anti-slip sheet,
A sheet made of polyethylene or polypropylene with a thickness of 2 mm and a length and width of 80 mm is placed on top of it, and a weight of 1 kg is placed on the sheet.
A load was applied. From this state, one side of the surface plate was pulled up at a constant speed of 100 mm/min, and the angle at which the placed sheet started to slide was measured (the angle with respect to the horizontal plane).
It is shown as the average value of times. (7) Hardness: 20℃ according to JIS K6301-81A method
Measured under constant temperature. (8) Deformation amount: Thickness 2mm, length and width 250mm on the surface plate
A sheet of anti-slip material with a diameter of 0.5 mm was placed, and the sheet was held at a constant temperature of 20°C using a metal jig with a width of 60 mm and a radius of 5 mm at the tip.
Pressing was carried out at a constant speed of mm/min, and the amount of sinking of the jig into the anti-slip material sheet and the load were read, and the amount of sinking was expressed as the amount of sinking when a load of 80 kg was applied. (9) Wear rate: Using a custom fabric abrasion tester manufactured by Daiei Kagaku Co., Ltd., a No. 40 side paper was brought into contact with a non-slip material with a length of 35 mm, a width of 20 mm, and a thickness of 2 mm. ) was applied and reciprocated at a constant temperature of 20°C with a stroke of 50 mm, and the anti-slip material was worn out by repeating 5000 reciprocations, and the amount of wear was expressed as a weight percentage of the original weight of the anti-slip material. In the tables of Examples, ethylene propylene rubber is abbreviated as "EPM," linear low density polyethylene is abbreviated as "LLD," and ethylene-vinyl acetate copolymer is abbreviated as "EVA." Examples 1-2 Ethylene propylene rubber (EPM) (manufactured by Japan EP Rubber Co., Ltd., ethylene propylene rubber
EP02P (ethylene content 74% by weight) and linear low density polyethylene (LLD) {melt index (190℃): 0.78g/10 min density: 0.92g/cm ³ } are blended in the proportions shown in Table 1 below. Then, it was made into pellets using an extruder {Tanabe Plastic Machinery Co., Ltd., VS30-22 type extruder, 30φ tip, dullage type, L/D: 22, compression ratio: 3.5}, and then press-formed to a thickness of 2 mm and a length of 250 mm. A sheet was prepared and used as an anti-slip material. (a) Heat welding of polypropylene molded products. Polypropylene {manufactured by Mitsubishi Yuka Co., Ltd., Mitsubishi Noblen BC-8, melt index (230℃):
1.2 g/10 minutes, density: 0.98 g/cm ³
The above-mentioned anti-slip material sheet was heat-welded by press molding at 230° C. and under pressure of 4 kg/cm ³ for 5 minutes. Table 1 shows various physical properties of the obtained anti-slip material. (b) Heat welding to polyethylene molded parts. Polyethylene {manufactured by Mitsubishi Chemical Industries, Ltd., Novatec JV 040C, melt index (190℃):
5.0 density: 3.5mm thickness manufactured using 0.96g/ ^cm3
The above-mentioned anti-slip material sheet was heat-welded to a plate-shaped body having a length and width of 250 mm by press molding at 190° C. and under pressure of 4 kg/cm ³ for 5 minutes. Table 1 shows various physical properties of the obtained anti-slip material. Example 3 The blend of ethylene propylene rubber and linear low density polyethylene shown in Example 1 was pelletized by passing it through an extruder twice to improve its dispersion and mixing properties. Other conditions were the same as in Example 1 to obtain a molded article with a non-slip material thermally welded. Table 1 shows various physical properties of the obtained anti-slip material. Example 4 A part of the linear low-density polyethylene was replaced with ethylene-vinyl acetate copolymer (manufactured by Sumitomo Chemical Co., Ltd., Evatate D2011, vinyl acetate content 5% by weight) in the proportions shown in Table 1. A molded article with a non-slip material thermally welded was obtained in the same manner as in Example 1 except for the above. Table 1 shows various physical properties of the obtained anti-slip material. Comparative Examples 1 to 3 Using the ethylene propylene rubber or linear low density polyethylene used in the examples, ethylene propylene rubber alone, linear low density polyethylene alone, or ethylene propylene rubber and linear low density polyethylene outside the scope of the present invention An anti-slip material prepared using a mixture of the following was treated in the same manner as in Example 1 to obtain a molded article with the anti-slip material heat-welded. Table 1 shows various physical properties of the obtained anti-slip material. Example 5 The pellets of Example 3 were made into a belt-shaped sheet with a thickness of 2 mm, width of 20 mm, and length of 1 m using an extruder, and the belt-shaped sheet was used as a non-slip material to form a pallet made using the same polypropylene as used in Example 3. A structure similar to that shown in FIG. 1 was heat welded to the surface. Thermal welding is performed by melting the anti-slip material and the surface of the pallet using hot air at a temperature of 700-800°C (built-in heater temperature) and a flow rate of 120/min, and pressing both together with a pressing force (roller linear pressure) of 2 kg/cm. I did it. The anti-slip material adheres well to the pallet,
The anti-slip properties were also sufficient for practical use.

[Table] For example, when this molded product is used as a pallet for transporting cargo, the polyolefin molded product to which the anti-slip material of the present invention is attached has good anti-slip properties between the product and the articles placed on the pallet. In addition, it is excellent in wear rate, welding strength, etc., and is very preferable for practical use.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a pallet which is an example of the molded product of the present invention. In the figure, 1 indicates a molded product (pallet), and 2 indicates a non-slip material.

Claims (1)

[Claims] 1. A non-slip polyolefin molded product obtained by thermally welding an anti-slip material to a polyolefin molded product,
The anti-slip material is ethylene propylene rubber 20~
80% by weight and linear low density polyethylene 80-20% by weight
1. An anti-slip polyolefin molded article, characterized in that the ethylene propylene rubber contains 60 to 80% by weight of an ethylene component and 40 to 20% by weight of a propylene component. 2. Claim 1, characterized in that when blending ethylene propylene rubber and linear low-density polyethylene, other thermoplastic synthetic resins are blended in an amount that does not exceed the blending amount of each of the two components. The polyolefin molded product described. 3. The polyolefin molded article according to claim 2, wherein the other thermoplastic synthetic resin is an ethylene-vinyl acetate copolymer. 4. The polyolefin molded article according to any one of claims 1 to 3, wherein the polyolefin is polypropylene. 5. The polyolefin molded article according to any one of claims 1 to 3, wherein the polyolefin is polyethylene.