JPH0232384B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a highly rigid cloth used for packaging and protecting various materials, cloth sheets, cloth bags, etc. More specifically, the present invention relates to a synthetic resin cloth made by weaving uniaxially stretched tape yarns of polyolefin resin. Traditionally, it has been woven using thermoplastic synthetic resin uniaxially stretched tape yarns as warp and weft for packaging and protecting various materials, such as heavy packaging bags or cloth sheets for rice bags, wool bags, flexible containers, etc. Crosses are widely used. The material resin that forms these cloths is generally a crystalline thermoplastic resin, and examples of the resin include polyolefin resins such as high-density polyethylene and polypropylene, polyamide resins, and polyester resins. Of these, polyolefin resins are most frequently used, especially in terms of versatility, processing stability, and low cost. Conventional cloths woven from uniaxially oriented tape yarns using polyolefin resins such as high-density polyethylene or polypropylene cannot yet be said to have sufficient rigidity and strength. That is, in order to improve the rigidity and strength of cloth using conventional material resins, uniaxially stretched tape yarns with higher fineness must be used, which increases longitudinal cracking during stretching and weaving. In particular, in the stretching step of the cloth manufacturing process consisting of stretching, winding, warping, and weaving, stretching breaks occur frequently, and embrittling vertical cracks occur in the winding, warping, and weaving steps. Various methods have been proposed to improve these drawbacks. For example, attempts have been made to add rubber or elastomers to conventional material resins, or to add inorganic particulates, but these methods have some effect on the longitudinal tearing properties of tape yarns with low fineness. It is less effective against embrittling cracks in high-density tape yarns. In addition, the rigidity of conventional cloth made of tape yarn with low fineness is insufficient, and for cloth for heavy packaging that requires high strength and high rigidity, it is necessary to use a two-layer cloth made by laminating two pieces of cloth together. However, the cost will also increase significantly. The present invention has been made as a result of intensive studies to solve the above problems. That is, the present invention is a crystalline polyolefin resin.
At least fineness consisting of an olefinic resin composition of 96 to 75% by weight and 4 to 25% by weight of an ethylene-α-olefin copolymer resin with a density of 0.89 to 0.94 g/cc
Woven from 2000 denier uniaxially stretched tape yarn,
If desired, a thermoplastic resin layer may be provided on at least one of the woven surfaces to increase the stiffness of the woven body by at least 10
The present invention provides a synthetic resin cloth with a particle size of 1.5 g/cm and a transportation bag for powder and granular materials made of the cloth. The crystalline polyolefin resin used in the present invention is an ethylene homopolymer with a density of 0.94 to 0.97 g/cc, a copolymer with α-olefin containing ethylene as a main component, or crystalline polypropylene, polybutene-1, polyolefin, etc. Examples include homopolymers of α-olefins such as -4-methylpentene-1, copolymers containing α-olefins as a main component, and mixtures of the above. The melt index of the above-mentioned crystalline polyolefin is not particularly limited, but generally, for example, high density polyethylene has a melt index of 0.5 to 1.5 g/10 minutes, and polypropylene has a melt index of 0.5 g/10 min.
A range of ˜4 g/10 minutes is preferred. On the other hand, ethylene-α- with a density of 0.89 to 0.94 g/cc
Olefin copolymer resin is generally 60~
95 mol% ethylene and 5-40 mol% carbon number 3~
A copolymer consisting of 12 α-olefins, such as ethylene-propylene copolymer, ethylene-propylene copolymer,
Examples include butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-4-methylpentene-1 copolymer, ethylene-octene-1 copolymer, etc., but in particular α- Copolymers with olefins are preferred. Moreover, these copolymers may be copolymerized with two or more types of α-olefins. The production methods for these copolymers include gas phase method,
Slurry method, solution method, high pressure method, etc. are not particularly limited, but the melt index of the above copolymer is from 0.5 to
A range of 4.0 g/10 minutes is preferred. The melt index of the mixture of crystalline polyolefin and ethylene-α-olefin copolymer is not particularly limited, but care must be taken not to cause poor kneading when mixing. In the present invention, the mixing ratio of the crystalline polyolefin and the ethylene-α-olefin copolymer is important;
It is necessary to mix in a proportion of 25% by weight. If the mixing ratio of the above-mentioned ethylene-α-olefin copolymer is less than 4% by weight, the tape yarn will have many longitudinal cracks, while if it exceeds 25% by weight, the stiffness of the cloth will decrease, which is not preferred. Other commonly used additives such as antioxidants, ultraviolet inhibitors, antistatic agents, or coloring pigments may be added to the polyolefin resin composition. In the present invention, a tape formed using the above-mentioned specific polyolefin resin composition is uniaxially stretched, wound up, warped, and woven into a synthetic resin cloth having a rigidity of at least 10 g/cm. When a resin composition outside the above composition range is used to increase the fineness of the tape yarn as in the present invention, stretch breakage is likely to occur during the stretching process. In particular, in the conventionally most widely used method of stretching while sliding a hot plate, the amount of heat transferred and received by the object to be stretched tends to be insufficient, resulting in significant stretching breakage. On the other hand, in the winding, warping, and weaving processes, vertical cracking of the tape yarn becomes a particular problem. A tape yarn with a high fineness has a relatively larger tape width and thickness than a tape yarn with a low fineness. Therefore, when a high fineness tape yarn with a thickness exceeding 35 to 40μ is formed from a conventional material resin as in the present invention,
The rigidity becomes excessive and, for example, when the tape yarn is folded along its length, longitudinal cracks occur along the creases, as if they were brittle fractures. This cracking does not stop at a short section, but propagates along the length, eventually leading to the tape yarn breaking. In addition, even slight mechanical stimulation causes vertical cracking similar to brittle fracture.
Such embrittlement cracking phenomenon causes frequent stoppages in the winding, warping, and weaving processes of the tape yarn, and can also cause stoppage accidents, especially due to the tape yarns rubbing against each other in the loom during weaving. This occurs frequently and makes it impossible to continue weaving, resulting in a significant drop in operating efficiency. Further, as mentioned above, tape yarns made of conventional resin materials have high rigidity, so they cannot be folded and have to be woven as they are. Therefore, it is difficult to increase the weave density. However, according to the present invention, by using a specific resin composition, it is possible to stably supply tape yarn with a high fineness of 2,000 denier or more without causing the above problems, and the tape yarn can be Since vertical cracks do not occur even when folded along the direction, double or triple folding is possible, and the weaving density can be increased, so the rigidity of the cloth can be significantly increased. Furthermore, as mentioned above, it is important for the performance of the cloth of the present invention to have a rigidity of at least 10 g/cm in order to have the same rigidity as a conventional two-layer bag. In order to obtain such a highly rigid cloth, for example, a tape yarn with a high fineness of at least 2000 denier and a weave density of at least 11
This can be obtained by weaving 11 pieces/inch, and it is also possible to sufficiently increase the cross strength. In the present invention, the method for producing the tape yarn and cloth is not particularly limited, and any conventionally known method may be used. For example, in the stretching process, a hot plate, a hot roll, a hot air oven, etc. can be used, and among these, the effects of the present invention can be fully exhibited especially in hot plate stretching in which the material is stretched while sliding on a hot plate. . The stretching ratio in the stretching process is
Although not particularly limited, a range of 5 to 9 times is usually preferred. Further, the loom used in the weaving process is not particularly limited, but a loom that includes a tube winding process in which the inner weft of the power loom is once wound onto a shuttle is not preferred. The tape yarn used in the present invention is a general term for common yarns such as flat yarn, split yarn, drawn tape, and slit yarn. In the present invention, if desired, by providing a thermoplastic resin layer on at least one of the cross surfaces, the functions of packaging and protecting various materials can be dramatically improved. The thermoplastic resin layer may be formed by a conventional method such as directly coating the cloth body with a molten resin, or bonding a thermoplastic resin film with an adhesive or directly heat-sealing it. When performing lamination, heat fusion, heat treatment, etc., the temperature must be within a range where the stretching effect of the cloth is not lost. Loss of the above-mentioned stretching effect is undesirable because it reduces mechanical strength such as strength and rigidity of the cloth body. The above-mentioned laminate of the present invention may be provided with a thermoplastic resin layer on one or both sides of the cloth body, and if necessary, can be made into a multilayer laminate structure in which the cloth body is further adhered on the thermoplastic resin layer. Good too. The above-mentioned thermoplastic resin may be the same type of resin as the cloth body or a different type of resin,
Examples include polyolefin resins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymers, polyamide resins, polyvinyl alcohol resins, polyester resins, and polyvinyl chloride resins, but are not particularly limited. As described above, the present invention provides a thermoplastic resin layer on at least one of the cloth body surfaces, thereby imparting convex strength, rigidity, tensile strength, airtightness, etc., and further improving its function as a heavy-duty packaging material. be able to. Another invention of the present application relates to a transportation bag for powder and granular materials that uses the synthetic resin cloth described above to dramatically improve transportation functions such as packaging and protection. For more details, see Crystalline Polyolefin Resin 96~
Ethylene-alpha with 75% by weight and density 0.89-0.94g/cc
- At least fineness consisting of a polyolefin resin composition containing 4 to 25% by weight of an olefin copolymer resin
Woven from 2000 denier uniaxially stretched tape yarn,
If desired, a thermoplastic resin layer is provided on at least one of the woven surfaces to increase the stiffness of the woven body to at least 10
This is a transportation bag for powder and granular materials, characterized in that a synthetic resin cloth having a weight of 1.5 g/cm is formed into a rectangular or cylindrical shape, and an input port and/or discharge port are provided at the upper and/or lower portions. There are no particular restrictions on the shape, dimensions, structure, etc. of the above-mentioned transportation bag for powder and granular materials (hereinafter referred to as "flexible container"). Alternatively, it may be of a well-known shape, such as one with an input port on the top surface and a discharge port on the bottom surface.By forming this flexible container with the cloth of the present invention, a flexible container that is superior to conventional ones can be produced at a lower cost. It can be provided to That is, since the flexible container of the present invention is constructed using the above-mentioned high-rigidity, high-strength cloth as a base fabric, it can be constructed by coating a conventional woven fabric using polyethylene terephthalate, nylon, etc. with rubber, polyvinyl chloride, etc. It has the same durability as a running type flexible container made of so-called tarpaulin, and can be manufactured at a much lower cost. On the other hand, in conventional flexible containers whose base fabric is made by laminating two or more cloths made of cloth or sheets made of tape yarns of about 1000 to 1500 denier, the strength decreases due to lamination, and each Functional deterioration is likely to occur due to variations in physical properties. Furthermore, there is an increase in the number of bonding steps and the generation of losses during the bonding process, which is disadvantageous in that it is extremely disadvantageous economically. In comparison, when using the cloth of the present invention, these problems are not present and the performance of the container is far superior. In addition, the flexible container of the present invention can be made of single cloth, single-sided laminated cloth, double-sided laminated cloth, or A base material such as the laminated structure of the laminate cloth is selected, a flexible container is created using these as the base fabric, and it is possible to use the flexible container according to the above-mentioned characteristics and functions. As mentioned above, the flexible container of the present invention is made of a base fabric with high strength and high rigidity, so it has excellent durability and impact resistance, and the manufacturing process can be greatly simplified, so it can be manufactured at a low cost, etc. It has the following advantages. EXAMPLES The present invention will be explained in more detail below using Examples and Comparative Examples, but the present invention is not limited to these Examples. Examples and Comparative Examples [Method for forming uniaxially oriented tape yarn and cloth] () Manufacture of uniaxially oriented tape yarn Various resin compositions were formed into a film with a thickness of about 130μ by an inflation film forming method. After slitting the tape yarn into ribbons with a width of 18 mm, the tape yarn was stretched using a hot plate uniaxial stretching method in which the ribbon was stretched while sliding it on a hot plate. , a uniaxially drawn tape yarn with a fineness of 2500 denier was prepared. The tape yarn at that time was about 6.5 mm wide x 45 μm thick. () Manufacture of Cloth After subjecting the above tape yarn to a warping process, a cloth with a weaving density of 12 warps x 12 wefts/inch was produced using a Sulzer loom (manufactured by Sulzer Brothers). [Resin and filler used] () Crystalline polyolefin (-1) High density polyethylene (density 0.957g/cc, melt index
1.2g/10min) (-2) Isotactic polypropylene (density 0.89g/cc, melt index
1.2g/10min) () Ethylene-α-olefin copolymer (-1) Ethylene-butene-1 copolymer (density 0.920g/cc, melt index
0.9 g/10 min, butene-1 content 12 mol%) (-2) Ethylene-hexene-1 copolymer (density 0.918 g/cc, melt index
1.0g/10 minutes, hexene-1 content 12 mol%) () Ethylene-propylene copolymer rubber (density 0.89g/cc) () Calcium carbonate (brand SCP-A, manufactured by Sankyo Seifun Co., Ltd.) [ Test method and evaluation method] *1 Stretchability...Number of cuts in 2 hours when 20 tape yarns are stretched (Evaluation method) ×...4 times or more △...2-3 times 〇...1 time ◎...0 times* 2 Strength (g/denier) Using Tensilon, it is pulled at a gripping interval of 300 mm and a pulling speed of 300 mm/min, and the value at which it breaks is divided by the fineness of the tape yarn *3 Cracking resistance...The value of the tape yarn after winding. Crack condition (evaluation method) ×... Completely cracked △... 2 to 3 places / 10 m length 〇... No crack / 10 m length * 4 strong (Kg / 5 cm width) Cloth sample: Take a 7 cm wide cloth and Remove warp threads 1cm wide from both sides, and make 5cm
It was used as a test piece of width (labeled strip). Laminated cloth sample: The laminated cloth was cut into a 5 cm wide test piece (cut strip). Tensile speed: 200mm/min Grasp interval: 200mm *5 Rigidity (g/cm)...Average bending strength measured by handrometer when width is 1cm and span is 4cm *6 Weaving efficiency...When weaving 10m of cloth Number of loom operation stoppages due to yarn fraying (Evaluation method) ×...3 to 4 times/10m △...1 to 2 times/10m 〇...None/10m Examples 1-1 to 1-3, Comparative Examples 1-1 to 1 ~3 High density polyethylene (-1) as material resin
and ethylene-butene-1 copolymer (-1) were used to form tape yarns and cloths as described above, and the effects of various mixing ratios were evaluated.
Shown in the table. As a result, a blend of 2% by weight of the high-density polyethylene of Comparative Example 1-1 outside the present invention and the ethylene-butene-1 copolymer of Comparative Example 1-2 had excellent stretchability, cracking resistance, and weaving properties. less efficient,
Ethylene-butene-1 copolymer 30 of Comparative Example 1-3
When the weight percentage is blended, the stiffness of the cloth is inferior.
In Examples 1-1 to 1-3, test results such as stretchability, cracking resistance, weaving efficiency, and others were all good. Example 2 and Comparative Examples 2-1, 2-2 Ethylene-butene- of Example 1 as the material resin
1 copolymer (-1) with ethylene-hexene-1
The same procedure as in Example 1 was carried out except that (-2) was changed, and the results are shown in Table 1. As a result, Comparative Examples 2-1 and 2-2 were compared to Comparative Examples 1-1 to 1-3.
showed similar results. In contrast, the results of Example 2 were all good. Comparative Examples 3-1 to 3-3 High density polyethylene (-1) as material resin
The test was carried out in the same manner as in Example 1 using a composition in which ethylene-propylene copolymer rubber (2) or calcium carbonate (2) was mixed, and the results are shown in Table 1. As a result, cracking resistance, weaving efficiency, or stretchability were poor in both Comparative Examples 3-1 and 3-
In No. 2, the rigidity is also inferior. Examples 3-1 to 3-3, Comparative Example 3-4 Ethylene-butene-1 copolymer (-1) and ethylene-hexene-1 copolymer based on isotactic polypropylene (-2) as the material resin (-2) and ethylene-propylene copolymer rubber () were blended, respectively, and Example 1
Evaluations were made in the same manner as above, and the results are shown in Table 1. As a result, the comparative example, which was a blend of ethylene-propylene copolymer rubber, was inferior in cracking resistance and weaving efficiency. Comparative example 4 High density polyethylene (-1) as material resin
and ethylene-butene-1 copolymer (-1) to create a tape yarn with a fineness of 1500 denier, form a cloth, and measure the physical properties of the cloth,
The results are shown in Table 1. As a result, the stiffness is 3
It was an inferior cloth of ~4 g/cm. Comparative Example 5 Fineness 1000 made of high-density polyethylene (density 0.957 g/cc, melt index 1.2 g/10 minutes)
Tape yarn with a denier and a strength of 5 g/denier was woven at a weave density of 12 threads x 12 threads/inch. Made of the same resin as the cloth, fineness 1500 denier strength 5g/
Weave denier tape yarn at a density of 12 x 12/
After laminating the 50μ thick woven cloth through an extruded laminate layer of low density polyethylene (density 0.925g/cc, melt index 8.5g/10 minutes), the above-mentioned 50μ thick cloth was attached on both sides. A laminate layer of low density polyethylene was formed.
The basis weight of this cloth sheet is 380g/ ^m2 , the strength of this cloth sheet is 170Kg/5cm width, and the rigidity is 18g/m2.
It was cm. Example 4 Low-density polyethylene (density 0.925 g/cc, melt index 8.5 g/10 minutes) was extruded and laminated on both sides of the cloth of the present invention obtained in Example 1-2, and a 75μ thick layer was laminated on both sides of the cloth. The strength of the cloth sheet was measured by forming a laminate layer of low-density polyethylene and setting the basis weight to 375g/ ^m2 , which is almost the same as in Comparative Example 5.The strength was 185Kg/5cm width, and the rigidity was 30.
g/cm, which is very high, and is superior to the cloth sheet of Comparative Example 5, indicating that the effects of the present invention are remarkable. 【table】

Claims (1)

[Scope of Claims] 1. A polyolefin resin composition having a fineness of at least 2000 and comprising 96 to 75% by weight of a crystalline polyolefin resin and 4 to 25% by weight of an ethylene-α-olefin copolymer resin having a density of 0.89 to 0.94 g/cc. A synthetic resin cloth woven from denier uniaxially stretched tape yarns and having a stiffness of at least 10 g/cm. 2. The synthetic resin cloth according to claim 1, wherein a thermoplastic resin layer is provided on at least one of the woven surfaces of the synthetic resin cloth. 3. Claim 1, characterized in that the uniaxially stretched tape yarn is woven in a state in which it is folded into at least two layers along its length.
Synthetic resin cloth according to item 1 or 2. 4. The synthetic resin cloth according to any one of claims 1 to 3, wherein the ethylene-α-olefin copolymer is an ethylene-butene-1 copolymer. 5. The synthetic resin cloth according to any one of claims 1 to 3, wherein the ethylene-α-olefin copolymer is an ethylene-hexene-1 copolymer. 6 Uniaxially oriented tape yarn with a fineness of at least 2000 denier, consisting of a polyolefin resin composition containing 96 to 75% by weight of a crystalline polyolefin resin and 4 to 25% by weight of an ethylene-α-olefin copolymer resin having a density of 0.89 to 0.94 g/cc. A synthetic resin cloth woven with a stiffness of at least 10 g/cm is formed into a rectangular or cylindrical shape, and an input port and/or discharge port are provided at the upper and/or lower portions. Transport bag for powder and granular materials. 7. The transportation bag for powder or granular material according to claim 6, characterized in that a thermoplastic resin layer is provided on at least one of the woven surfaces of the synthetic resin cloth.