JP2006045685A - Tarpaulin made of polyolefin-based resin excellent in heat-resistant creeping property - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide tarpaulin made of a polyolefin-based resin having good flexibility, enabling high-frequency welder fusion, having high breakage strength of a high-frequency welder fusing part, excellent in a heat-resistant creeping property and suitable, especially as a material for flexible container formation and excellent in heat resistance characteristics. <P>SOLUTION: The tarpaulin is obtained by forming a polyolefin-based resin layer containing 100 pts. mass one or more kinds of ethylenic copolymer resin selected from ethylene-vinyl acetate copolymer resin and ethylene (meth)acrylic acid (ester) copolymer resin and 0.5-20 pts. mass cyclic imino-ether group-containing copolymer resin and as necessary, blending one or more kinds of resins selected from a polyethylene resin, an ethylene-α-olefin copolymer resin and a polypropylene resin alloy therein on both surfaces of a fibrous base fabric. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyolefin resin tarpaulin excellent in heat-resistant creep resistance. More specifically, the present invention has good flexibility and excellent heat-resistant creep resistance, and has a high fracture strength when fused and sewn with a high-frequency welder, thereby forming a flexible container in particular. The present invention relates to a polyolefin-based resin tarpaulin suitable as a sheet material.

Conventionally, as a material for forming a flexible container, (1) a polyolefin-based resin is extruded onto one or both sides of a fibrous base fabric made of a slit yarn or a split yarn manufactured from a polyolefin resin such as polypropylene and polyethylene. Tarpaulins obtained by laminating, (2) Tarpaulins obtained by laminating soft polyvinyl chloride resin films on both surfaces of a fibrous base fabric made of synthetic resin multifilaments such as polyester multifilaments, and (3 ) A layer obtained by laminating a polyolefin copolymer resin film such as ethylene-vinyl acetate copolymer resin on both sides of a fibrous base fabric made of synthetic resin multifilament such as polyester multifilament by calendering. Porin, etc. have been known.
The polyolefin resin-coated tarpaulin (1) is often used for simple containers and is lightweight and inexpensive. However, it is inflexible and cannot be fused with a high-frequency welder, so sewing with a sewing machine is required. In addition, since the coating layer is thin, the durability is generally low and it cannot be used repeatedly over a long period of time. The soft polyvinyl chloride resin film laminated tarpaulin (2) has excellent durability and flexibility and is suitable for fusion with a high-frequency welder. However, since the specific gravity of the soft polyvinyl chloride resin is high, it becomes heavy overall. There was a problem that handling was difficult. Tarpaulin (2) contains phthalate esters that are suspected as endocrine disrupters when it is disposed of as a plasticizer. There is a concern that the plasticizer may be eluted and mixed into the groundwater, and the polyvinyl chloride resin contains a chlorine component, so that it cannot be incinerated. Furthermore, the polyolefin-based copolymer resin film laminated tarpaulin (3) does not reach the tarpaulin (2), but has practically considerable durability and flexibility, and can be fused by a high-frequency welder. Because it is lighter than tarpaulin (2) and does not contain plasticizers or chlorine components, there are few problems during disposal, so it is widely used mainly for transportation and storage of resin pellets and granular materials. Became.
However, the flexible container manufactured using the tarpaulin (3) has a heat resistant creep resistance of the fused part by the high frequency welder due to the melting point of the polyolefin copolymer resin, compared with the flexible container obtained from the tarpaulin (2). Has the disadvantage of being inferior. Therefore, in this container, for example, when resin pellets are filled at a temperature exceeding 50 ° C., the resin softens in the fusion part of the container and the strength of the fusion part decreases, and the flexible container is deformed, Bags may be broken during transportation, which is a major problem in terms of work safety and logistics efficiency.

There are two reasons why the tarpaulin (3) is inferior in heat-resistant creep resistance. One is the low adhesion between the fibrous base fabric made of polyester multifilament and the polyolefin copolymer resin film such as ethylene-vinyl acetate copolymer resin, and the other is the polyolefin copolymer resin film. The softening temperature of is low.
For this reason, for example, in order to improve the adhesion between the fibrous base fabric and the ethylene-vinyl acetate copolymer resin film, attempts have been made to apply an adhesive treatment to the fibrous base fabric. Many of the adhesives that can be used have low heat resistance, and the adhesive layer itself is softened in an environment exceeding 50 ° C., so that the adhesive effect is extremely reduced. In order to improve this drawback, a method of performing an adhesion treatment using a mixed solution of polyurethane and a crosslinking agent has also been performed, and according to this method, it is possible to improve heat-resistant creep resistance and adhesion. However, another problem occurs in the mechanical performance of the tarpaulin, such as the texture of the obtained tarpaulin becomes hard and the tear strength is lowered.

  In addition, as a fiber constituting the fibrous base fabric, a multifilament yarn in which an ethylene-vinyl acetate copolymer resin and a highly adhesive polyethylene fiber are mixed and twisted is used (for example, JP-A-7-54239, Patent Document 1). However, according to this method, although the adhesion between the base fabric and the resin layer is improved, the thermal resistance of the obtained tarpaulin is still insufficient, and the texture of the obtained tarpaulin It has been confirmed that a problem arises in that the hardness becomes low and the tear strength decreases.

  In order to increase the softening temperature of the resin laminated on both the front and back sides of the base fabric, an ethylene-vinyl acetate copolymer resin with a low vinyl acetate component is used, or a polyolefin resin having a higher softening temperature than the ethylene-vinyl acetate copolymer resin. For example, a method of blending ethylene-α-olefin copolymer resin, polypropylene elastomer, or the like is conceivable. However, in this method, the content ratio of the vinyl acetate component having polarity is lowered, so that fusion by a high-frequency welder is performed. There was a problem that the tarpaulin obtained at the same time became insufficient and the flexibility of the tarpaulin obtained was insufficient.

  In order to improve the high frequency welder property, a method of adding 5-200 phr of an inorganic substance having a product of dielectric constant and dielectric loss (ε · tan δ) of 0.1 or more to the resin layer is known ( For example, Japanese Examined Patent Publication No. 59-46774, Patent Document 2), which makes it possible to fuse the obtained resin layer with a high-frequency welder even if the content ratio of vinyl acetate is low to some extent. However, it does not solve the problem of flexibility of the obtained tarpaulin, and the inorganic substance is not effective when added in a small amount, and a large amount of addition is necessary to obtain the effect. There existed a problem that the softness | flexibility and resin physical property of a resin composition fell, and also the workability at the time of shaping | molding also fell.

  Further, a method of crosslinking a polyolefin copolymer resin layer by radiation irradiation (for example, JP-A-8-1874, Patent Document 3) and water crosslinking by a crosslinkable polyolefin copolymer resin are known. However, in the above-mentioned radiation cross-linking, the heat resistance creep resistance of the resin layer to be obtained is improved, but due to this heat resistance improvement, it becomes difficult to heat-seal with a high frequency welder, etc. This improvement method itself lacks versatility because it requires a large amount of equipment. Further, the water-crosslinked polyolefin is inferior in processing stability, and further, it is necessary to immerse the molded product in water for one day or more, which is not particularly suitable for the production of a flexible container.

  As a simple method of forming resin crosslinks, the polyisocyanate compound is uniformly mixed in the resin layers laminated on both the front and back surfaces to increase the softening temperature of the resin and at the same time provide an adhesive force between the fibrous base fabric. However, polyisocyanate compounds are not yet practical because of their rapid reaction and difficulty in uniform dispersion and seizure on metal hot rolls of molding machines.

  Although not suitable for the production of flexible containers, it is impregnated with an aqueous dispersion composition in which 1 to 10 parts by mass of an oxazoline group-containing aqueous crosslinking agent is blended with a fibrous (synthetic fiber) base fabric (for example, JP Japanese Patent Laid-Open No. 2002-3690 and Patent Document 4) have also been proposed. According to this method, the adhesion between the fibrous base fabric and the coating resin can be improved and the softening temperature of the resin can be improved at the same time. However, the liquid composition is waterproof against the open fibrous base fabric for flexible containers. It is difficult to form a coating layer. The waterproof coating layer can be formed from this liquid composition with a high-density fiber base fabric (however, multiple coating and impregnation steps are required), but the sheet obtained by this method is Since the fibrous base fabric is impregnated / crosslinked with a resin, the tear strength is low and the texture is hard, so that it is not suitable for a flexible container.

JP 7-54239 A Japanese Examined Patent Publication No.59-46774 JP-A-8-1874 Japanese Patent Laid-Open No. 2002-3690

  The present invention solves the above-mentioned problems of the prior art, has good flexibility, is capable of high-frequency welder fusion, has a high fracture strength at the high-frequency welder fusion part, and is excellent in heat-resistant creep resistance. An object of the present invention is to provide a polyolefin resin tarpaulin which is suitable as a material for forming a flexible container and has excellent heat resistance.

  In order to solve the above problems, the present inventors have intensively studied and, as a result, by blending a specific amount of a cyclic iminoether group-containing copolymer resin in the polyolefin resin composition, the heat-resistant creep resistance was remarkably improved. It has been found that a polyolefin resin tarpaulin is obtained, and the present invention has been completed.

That is, the polyolefin resin tarpaulin excellent in heat-resistant creep of the present invention is a film material including a fibrous base fabric and a polyolefin resin layer laminated on both front and back surfaces thereof, and the polyolefin resin layer The polyolefin-based resin composition for forming (a) ethylene comprising at least one selected from ethylene-vinyl acetate copolymer resin and ethylene- (meth) acrylic acid (ester) copolymer resin as its main resin component And (b) 0.5 to 20 parts by mass of a cyclic imino ether group-containing copolymer resin with respect to 100 parts by mass of the main resin component as a heat resistant creep resistance improving component. To do.
In the polyolefin resin tarpaulin excellent in heat-resistant creep of the present invention, the polyolefin resin layer is further selected from (c) a polyethylene resin, an ethylene-α-olefin copolymer resin, and a polypropylene resin alloy as a blend component. One or more additional polyolefin resins may be contained in a proportion of 70% by mass or less based on the main resin component (a).
In the polyolefin resin tarpaulin excellent in heat-resistant creep property of the present invention, in the main resin component of the polyolefin resin layer, the total mass of vinyl acetate and (meth) acrylic acid (ester) contained as a comonomer However, it is preferable that it is 5-30 mass% with respect to the mass of the said main resin component (a), or the total mass of the main resin component (a) and an additional blend component (c).
In the polyolefin resin tarpaulin excellent in heat-resistant creep of the present invention, a cross-linked structure by ring-opening of the cyclic iminoether group-containing copolymer resin is formed at the lamination interface between the polyolefin resin layer and the fibrous base fabric layer. Preferably it is formed.
In the polyolefin resin tarpaulin excellent in heat-resistant creep of the present invention, the cyclic imino ether group-containing copolymer resin preferably has an oxazoline group represented by the following chemical formula (1).

  According to the present invention, it has good workability and flexibility, high-frequency welder fusion is possible, the fracture strength of the high-frequency welder fusion part is high, and the heat-resistant creep property is remarkably improved. A polyolefin resin tarpaulin excellent in heat-resistant creep resistance, which is suitable as a forming material, can be provided.

  The polyolefin resin tarpaulin excellent in heat-resistant creep property of the present invention (hereinafter referred to as polyolefin resin tarpaulin) is a film material in which a polyolefin resin layer is laminated on both front and back surfaces of a fibrous base fabric. The polyolefin resin composition forming the polyolefin resin layer is (a) one kind selected from ethylene-vinyl acetate copolymer resin and ethylene (meth) acrylic acid (ester) copolymer resin as its main resin component In addition, (b) as a heat resistant creep resistance improving component, 0.5 to 20 parts by mass of a cyclic iminoether group-containing copolymer resin with respect to 100 parts by mass of the main resin component (a), and If necessary, (c) as an additional blend component, polyethylene resin, ethylene-α-olefin copolymer resin, and polypropylene resin Additional polyolefin-based resin comprising one or more selected from alloy, with respect to the main resin components (a), at a ratio of 70 mass% or less, those containing.

  As a fiber material used for the fibrous base fabric that can be used for the polyolefin-based resin tarpaulin of the present invention, polypropylene fibers, polyethylene fibers, polyester fibers, nylon fibers, synthetic fibers such as vinylon fibers, natural fibers such as cotton and hemp, Examples include semi-synthetic fibers such as acetate, inorganic fibers such as glass fibers, silica fibers, alumina fibers, and carbon fibers. These fibers may be composed of single or a mixture of two or more types, and the shape is multifilament. , Short fiber spun yarn, monofilament, split yarn, tape yarn, etc. may be used, but in consideration of versatility, processability and adhesion / reactivity with cyclic iminoether compounds, it is possible to use polyester multifilament. preferable. The fibrous base fabric may be either a woven fabric or a knitted fabric. In the case of a woven fabric, it may have any structure such as plain weave, twill weave, and satin weave. From the balance, plain woven fabric is most preferable.

  The polyester multifilament yarn used for the fibrous base fabric is preferably 139 dtex (125 denier) to 2222 dtex (2000 denier), more preferably 278 dtex (250 denier) to 1111 dtex (1000 denier). If the fineness of the multifilament yarn is less than 139 dtex (125 denier), the resulting tarpaulin may have insufficient tear strength, and if it exceeds 2222 dtex (2000 denier), the breaking strength and tear strength of the resulting tarpaulin may be Although the diameter of the yarn becomes thicker, it is necessary to thicken the polyolefin resin layer to be laminated to cover it. As a result, the resulting tarpaulin is thicker and heavier, so its lightness and flexibility May become insufficient.

  The fibrous base fabric is preferably a stitched (coarse) plain woven fabric in which voids are formed between yarns. The number of warps and wefts to be driven is not particularly limited, but a plain weave obtained by driving 8 to 38 multifilament yarns of 139 dtex to 2222 dtex (125 to 2000 denier) per 25.4 mm (1 inch) respectively. It is preferable to use a cloth. For example, in the case of a multi-filament yarn of 555 dtex (500 denier), in the case of a multi-filament yarn of 1111 dtex (1000 denier), a plain woven fabric obtained with 14 to 24 yarns per inch. Is preferably used as the fibrous base fabric of the present invention, such as a plain woven fabric obtained by placing 12 to 22 per 25.4 mm (1 inch). The inter-thread void ratio of these fibrous base fabrics is preferably 5 to 30%, and more preferably 8 to 24%. Here, the porosity can be obtained as a value obtained by subtracting 100 from the percentage of the area of the yarn occupied in the unit surface area of the fibrous base fabric. The porosity is preferably calculated as an area of 10 cm in the warp direction × 10 cm in the weft direction as the surface unit area. If the porosity of the fibrous base fabric is less than 5%, the yarn density is too high, and the flexibility of the resulting tarpaulin may be insufficient, and the polyolefin system laminated on the front and back surfaces of the fibrous base fabric In some cases, the resin layer may have a poor mutual fusing property and insufficient dynamic durability. On the other hand, if the porosity exceeds 30%, the mutual bondability and flexibility between the resin layers are improved, but the yarn density in each direction of the process becomes too small, so that the dimensional stability of the resulting laminated sheet is not good. May be enough.

  The fibrous base fabric may be coated with an adhesive. In this case, the adhesive used is not particularly limited, but an aqueous adhesive such as acrylic, urethane, or vinyl acetate is preferably used. At this time, by adding an emulsion of a cyclic iminoether group-containing copolymer to the adhesive, the adhesive force between the polyolefin resin layer laminated on both the front and back surfaces and the fibrous base fabric is further improved, and heat creep resistance is also improved. It is expected to improve. The emulsion of cyclic iminoether group-containing copolymer may itself be used alone as a primer. The fibrous base fabric may be further subjected to a pretreatment such as a water absorption preventing treatment or a flameproofing treatment as necessary as long as the adhesiveness is not impaired.

The polyolefin resin composition forming the polyolefin resin layer of the polyolefin resin tarpaulin of the present invention is selected from (a) an ethylene-vinyl acetate copolymer resin and an ethylene- (meth) acrylic acid (ester) copolymer resin. A main resin component made of one or more ethylene copolymer resins and a heat resistant creep resistance improving component made of a cyclic imino ether group-containing copolymer resin are contained as essential components. As main resin components, an ethylene-vinyl acetate copolymer resin having a density of 0.880 to 0.960 g / cm ² and an MFR (melt flow rate: 190 ° C., 2.16 kg load): 0.3 to 10 g / 10 min. And ethylene-based copolymer resins made of a single or a combination of two or more such as ethylene- (meth) acrylic acid (ester) copolymer resins. The ethylene-vinyl acetate copolymer resin is obtained by copolymerization of an ethylene monomer and a vinyl acetate monomer, and the ethylene- (meth) acrylic acid (ester) copolymer resin is an ethylene monomer and (meth) acrylic acid ( Obtained by copolymerization with ester) monomers. Here, “(meth) acrylic acid (ester)” includes acrylic acid, methacrylic acid, acrylic acid ester, and methacrylic acid ester. These may be used alone in the copolymerization, or may be used as a mixture of two or more.

〔但し、式（２）中、Ｒ₁、Ｒ₂は、それぞれ互に独立に、水素原子、または炭素原子数１〜１８の不活性炭化水素置換基を表し、Ｒ₃は炭素原子数２〜８のアルケニル基を表し、ｎは１〜５の整数を表す〕
を有するものであれば、特に限定はなく、例えば、２−ビニル−２−オキサゾリン、２−ビニル−４−メチル−２−オキサゾリン、２−ビニル−５−メチル−２−オキサゾリン、２−イソプロペニル−２−オキサゾリン、２−イソプロペニル−４−メチル−２−オキサゾリン、２−イソプロペニル−５−メチル−２−オキサゾリン、２−ビニル−１，３−オキサジン、２−イソプロペニル−１，３−オキサジン、などを包含する、これらの環状イミノエーテル基含有モノマーは１種または２種以上の混合物として用いることができる。環状イミノエーテル基が５員環の構造をもつオキサゾリン基であるモノマーが本発明に好ましく用いられる。 The heat resistant creep resistance improving component (b) is composed of a cyclic imino ether group-containing copolymer resin obtained by copolymerizing a monomer containing a cyclic imino ether group and a different monomer copolymerizable with this monomer. is there. The cyclic iminoether group-containing monomer has the following structure:

[In the formula (2), R ₁ and R ₂ each independently represent a hydrogen atom or an inert hydrocarbon substituent having 1 to 18 carbon atoms, and R ₃ represents 2 to 2 carbon atoms. 8 represents an alkenyl group, and n represents an integer of 1 to 5.
For example, 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl -2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, 2-vinyl-1,3-oxazine, 2-isopropenyl-1,3- These cyclic imino ether group-containing monomers including oxazine and the like can be used as one kind or a mixture of two or more kinds. A monomer in which the cyclic imino ether group is an oxazoline group having a 5-membered ring structure is preferably used in the present invention.

  The heterogeneous monomer copolymerized with the cyclic imino ether group-containing monomer is not particularly limited as long as it is a monomer that can be copolymerized with the cyclic imino ether group-containing monomer and does not react with the cyclic imino ether group. For example, styrene, o- Styrene substitutes such as methylstyrene, p-methylstyrene, α-methylstyrene, vinyl aromatics such as vinylnaphthalene and vinylanthracene, vinyl cyanides such as (meth) acrylonitrile, acrylic acid esters and methacrylic acid esters, etc. Esters, unsaturated amides such as (meth) acrylamide and N-methylol (meth) acrylamide, vinyl esters such as vinyl acetate and vinyl propionate, vinyl ethers such as methyl vinyl ether, and α-olefins such as ethylene and propylene Emissions, vinyl chloride, halogen-containing α, such as vinylidene chloride, and the like can be illustrated β- unsaturated monomers, they may be used as alone or in combination one.

  Of all the monomers used in the cyclic iminoether group-containing copolymer resin, the content of the monomer containing a cyclic iminoether group is preferably 1 to 60% by mass. If it is less than 1% by mass, the effect of improving the fracture strength and heat-resistant creep resistance of the high-frequency welder weld may be insufficient, and if it exceeds 60% by mass, the melt viscosity will be high, which adversely affects workability. May affect. In the resin composition for polyolefin resin layers, the addition amount of the cyclic imino ether group-containing copolymer resin (b) is 0.5 to 20 parts by mass with respect to 100 parts by mass of the ethylene copolymer resin (a). It is preferable that it is 1-15 mass parts. If it is less than 0.5 part by mass, the obtained tarpaulin hardly obtains the effect of improving the fracture strength and heat-resistant creep property of the high-frequency welder fusion part. Moreover, even if it is added in excess of 20 parts by mass, the adhesive strength with the fibrous base fabric is saturated and there is no further improvement, which is uneconomical, and since the resulting polyolefin resin layer becomes hard, the flexibility of tarpaulin The processability is impaired, and the processability is also adversely affected. In the tarpaulin of the present invention, the polyolefin resin layer contains a cyclic iminoether group-containing copolymer resin, whereby the heat resistance of the polyolefin resin layer is improved, and the adhesion between the polyolefin resin layer and the fibrous base fabric is improved. Therefore, the fracture strength and heat-resistant creep resistance of the high-frequency welder fusion part are improved. This is because, for example, a heat-resistant crosslinked structure is formed in the polyolefin resin layer by ring opening of the cyclic iminoether group, and the ring opening of the cyclic iminoether group is further formed at the lamination interface between the polyolefin resin layer and the fibrous base fabric layer. This is due to the formation of a cross-linked adhesive structure. Further, the cyclic imino ether group captures the free acid, thereby improving the heat resistance stability of the polyolefin resin layer and suppressing the generation of odor.

The polyolefin resin layer of the polyolefin resin tarpaulin of the present invention is further added as an additional blending component (c) in addition to the components (a) and (b) for the purpose of improving heat-resistant creep resistance, wear resistance and the like. ), An additional polyolefin resin composed of one or more selected from polyethylene resin, ethylene-α-olefin copolymer resin, and polypropylene resin alloy is 70% by mass or less based on the main resin component (a), preferably You may contain in the ratio of 1-70 mass%.
Examples of the polyethylene resin include polyethylene resins having a density of 0.850 to 0.930 g / cm ² and MFR (melt flow rate: 190 ° C., 2.16 kg load) 0.5 to 20 g / 10 min. The ethylene-α-olefin copolymer resin is a copolymer of an ethylene monomer and an α-olefin monomer having 3 to 18 carbon atoms, particularly an α-olefin monomer having 4 to 10 carbon atoms, and has a density of 0.8. Those having 850 to 0.930 g / cm ² , MFR: (melt flow rate: 190 ° C., 2.16 kg load): 0.3 to 30 g / 10 min, preferably 1 to 20 g / 10 min are preferable. Preferred α-olefins include propylene, butene-1,4-methylpentene-1, hexene-1, heptene-1, octene-1, nonene-1, decene-1, and the like, What was obtained by copolymerizing 2 or more types with an ethylene monomer can be used. Further, the polypropylene resin alloy has a density of 0.850 to 0.930 g / cm ² , MFR (melt flow rate: 230 ° C., 2.16 kg load): 0.5 to 50 g / 10 min, preferably 1 to 20 g / For example, a blend resin of polypropylene and ethylene propylene rubber, a reactor resin in which a propylene / ethylene component is graft-polymerized on polypropylene, a reactor resin in which an ethylene / propylene non-common diene component is graft-polymerized on polypropylene, polypropylene and polymethyl A blend resin of methacrylate, a blend resin of polypropylene and a polyester resin, and the like can be mentioned. In particular, a propylene / ethylene component or an ethylene / propylene non-conjugated diene component is grafted to polypropylene. A polymerized reactor resin is preferably used from the viewpoint of processability and flexibility of the obtained tarpaulin. Furthermore, the polypropylene resin alloy may contain a compatibilizer and a modifier. The ratio of the blend amount of these additional polyolefin-based resins is 70% by mass or less, preferably 1 to 70% by mass, particularly preferably 10 to 60% by mass, based on the main resin component (a). -50% is more preferable. If the proportion of the additional blend component (c) exceeds 70% by mass, the resulting tarpaulin may become hard and the high frequency welder weldability may be impaired.

  In the polyolefin resin layer of the tarpaulin of the present invention, a cyclic imino ether group with respect to a total of 100 parts by mass of the ethylene copolymer resin-containing main resin component (a) and the polyolefin blend resin-containing additional blend component (c) The addition amount of the containing copolymer resin component (b) is preferably 0.5 to 20 parts by mass, and more preferably 1 to 15 parts by mass. If it is less than 0.5 part by mass, the obtained tarpaulin may hardly obtain the effect of improving the fracture strength and heat-resistant creep property of the high-frequency welder fusion part. Moreover, even if it is added in excess of 20 parts by mass, the adhesive strength with the fibrous base fabric is saturated, there is no further improvement, it is uneconomical, and the polyolefin resin layer becomes hard. Flexibility may be insufficient, and workability may be adversely affected.

  The total content of vinyl acetate and (meth) acrylic acid (ester) monomer in the total resin mass of the polyolefin-based resin layer is preferably 5 to 30% by mass, and preferably 10 to 25% by mass. Further preferred. If it is less than 5% by mass, the high frequency welder property of the obtained tarpaulin may be insufficient, and if it exceeds 30% by mass, the heat resistance and strength of the resin will be lowered, and the high frequency welder fusion part Breaking strength and heat-resistant creep resistance may be insufficient.

  The polyolefin resin layer of the present invention may contain silica for the purpose of improving processability and high frequency welder meltability. The silica used for this purpose is not particularly specified for its production method or particle diameter, but it has a water content of 3 to 15% by mass obtained by a general wet method, dry synthesis method or airgel synthesis method. Synthetic amorphous silica is preferably used. The average aggregate particle diameter of the synthetic amorphous silica is preferably 1 to 20 μm (Cole counter method), and more preferably 2 to 10 μm. The addition amount of silica is preferably 2 to 20 parts by mass and more preferably 3 to 10 parts by mass with respect to 100 parts by mass of the polyolefin resin layer. If it is less than 2 parts by mass, it cannot be expected to improve the high frequency welder meltability in the tarpaulin obtained, and if it is more than 20 parts by mass, the processability when processing the polyolefin resin composition into a film shape In some cases, the film appearance obtained by calendering may be poor, or the resin strength may be insufficient.

  A lubricant can be added to the polyolefin resin layer of the tarpaulin of the present invention for the purpose of improving the film moldability of the polyolefin resin composition forming the same. Examples of the lubricant to be used include phosphate ester type, aliphatic amide type, and montanic acid type. The addition amount of the lubricant is preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the polyolefin resin composition. If it is less than 0.1 part by mass, the effect of improving the processability of the polyolefin resin composition is dilute, and in the film obtained when it exceeds 3 parts by mass, the lubricant migrates to the surface, Adhesion between the base fabric and the polyolefin-based resin layer and lamination of the resin layers at the gaps (voids) in the fibrous base fabric are insufficient when laminated with the fibrous base fabric. Similarly, the printability of the tarpaulin obtained by the transfer of the lubricant to the surface may be insufficient.

  In the polyolefin resin layer of the tarpaulin of the present invention, other additives, that is, an ultraviolet absorber for improving durability, an antioxidant, a light stabilizer, an organic pigment for coloring, an inorganic pigment, A bright pigment, a flame retardant for imparting flame retardancy, and the like can also be included, and there is no particular limitation on the amount of these additives, and one or two or more of these are mixed and used as necessary. be able to.

  The polyolefin resin composition for a polyolefin resin layer in the tarpaulin of the present invention is molded into a film by a conventionally known molding method, for example, a T-die extrusion method, an inflation method, a calendar method, etc. Laminated on top. Especially in the processing of films colored with organic pigments, inorganic pigments, glitter pigments, etc., when the number of processing lots is relatively small and there are many color change operations, the calendering method is simple and reduces the loss of polyolefin resins. Is suitable. It is preferable that the film which comprises the polyolefin-type resin layer of this invention is manufactured in the temperature range of 100-200 degreeC by the calendar method. The thickness of the polyolefin resin film to be calendered is preferably 80 to 500 μm, and more preferably 120 to 350 μm. If the film thickness is less than 80μm, it is difficult to mold, and when laminated to a fibrous base fabric, the film breaks at the intersection of the fibrous base fabric, resulting in poor waterproofing and durability as a tarpaulin. It may become. Also, if it exceeds 500 μm, waterproofness and durability are sufficient, but since the amount of resin becomes excessive, the mass of tarpaulin becomes too large, and the resin layer becomes thick, so flexibility is impaired, etc. It may become a tarpaulin that is not easy to handle.

  In the polyolefin resin tarpaulin of the present invention, the polyolefin resin layer film is laminated on both front and back surfaces of a fibrous base fabric. As a method of laminating, a calender method, a T-die extrusion method, etc. is used to heat laminate on one side of a fibrous base fabric before the film is cooled and solidified, and repeat the same process once again to heat laminate on the opposite side. It may be made by topping method or T-die extrusion laminating method, and polyolefin resin film previously molded by calendar method, T-die extrusion method, inflation method, etc. is melted in a separate process with a thermal drum, infrared heater, etc. Alternatively, it may be carried out by a method of heat laminating one side or both sides of the fibrous base fabric in a semi-molten state. By heat laminating, the polyolefin resin layers laminated on both the front and back sides of the fibrous base fabric are integrated by bridging with each other. At this time, the cyclic structure contained in the polyolefin resin layer A crosslinked structure is easily formed by ring opening of the cyclic iminoether group of the iminoether group-containing copolymer resin, resulting in higher adhesion to the fibrous base fabric, and a polyolefin resin tarpaulin with excellent heat-resistant creep resistance. be able to. The thickness of the polyolefin resin tarpaulin of the present invention is preferably 0.20 to 1.50 mm, and more preferably 0.30 to 1.00 mm. If it is less than 0.20 mm, the durability may be insufficient, and if it exceeds 1.50 mm, it is excessively heavy and rigid, resulting in a tarpaulin with poor handling.

  The polyolefin resin tarpaulin of the present invention can be joined by a conventionally known method such as a fusion method using a high frequency welder, a fusion method using an ultrasonic welder, a hot air fusion method, or a hot plate fusion method. However, in the case of efficiently producing a product such as a flexible container having a three-dimensional and complicated three-dimensional structure, it is preferable to perform heat fusion sewing using a dedicated die by a high frequency welder fusion method.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to these. In the following examples and comparative examples, test methods for evaluating the flexibility, high-frequency welder fusing property, heat-resistant creep resistance and wear resistance of the polyolefin-based resin tarpaulin are as follows.

(I) Evaluation of flexibility A test piece cut to a width of 70 mm and a length of 30 mm was rolled to form a cylinder having a diameter of 20 mm and a length of 30 mm (the margin was fixed with a cyanoacrylate instantaneous adhesive), and an atmosphere at 20 ° C. The stress at the time of 50% compression (crushed until the diameter reaches 10 mm) was measured below, and the smaller the value, the more flexible the specimen was judged, and the following judgment was made.
A: Excellent flexibility (compressive stress: 150 g or less)
○: Good flexibility (151 to 175 g)
Δ: Slightly inferior (176 to 199 g)
X: Inferior in flexibility (200 g or more)
A loop stiffness tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used as a testing machine for evaluating flexibility.

(II) Evaluation of high-frequency welder fusing property The ends of two polyolefin resin tarpaulin specimens were stacked on a straight line with a width of 8 cm, and a weld bar of 8 cm x 30 cm (tooth shape: convex portions were linearly spaced with a 4 cm width at regular intervals. High frequency welder fusion machine equipped with 9 moldings / 25.4mm, height of convex part 0.5mm: concave parts 4cm wide, linear molding 9 lines / 25.4mm, concave part depth 0.5mm) A high frequency welder fusion bonding of polyolefin resin tarpaulin was performed using Yamamoto Vinita (YF-7000 type, manufactured by Co., Ltd .: output 7 KW) and evaluated.
○: Fusing is easy [Welder fusing conditions: fusing time 5 seconds, cooling time 5 seconds, anode current 0.8 A, weld bar temperature 40-50 ° C.]
(Triangle | delta): It can melt | fuse by strengthening a melt | fusion condition and lengthening a melt | fusion time.
[Welder fusion conditions: fusion time 10 seconds, cooling time 10 seconds, anode current 1.0 A, weld bar temperature 40-60 ° C.]
X: Even if the fusing conditions are strengthened and the fusing time is increased, the fusing is not performed.
[Welder fusion conditions: fusion time 10 seconds, cooling time 10 seconds, anode current 1.3 A, weld bar temperature 40-60 ° C.]

(III) Evaluation of heat-resistant creep resistance The heat-resistant creep resistance test was carried out by taking a sample having a width of 3 cm and a length of 30 cm including a fusion-bonded portion from a polyolefin-based resin tarpaulin which was fusion-bonded with a high-frequency welder as in the case of (II). Using this as a heat-resistant creep test piece, using a creep tester (Toyo Seiki Seisakusho Co., Ltd .: 100LDR type), a heat-resistant creep resistance test was conducted at 60 ° C. × 392 N (40 kgf) load × 24 hours. Were evaluated as follows.
◯: After 24 hours, the joint was not broken and was able to withstand a load of 60 ° C. × 392 N.
(Triangle | delta): Although it endured over 10 hours, the junction part sheared and destroyed within 24 hours. (Break time notation)
X: The joint part sheared and destroyed within 10 hours. (Break time notation)
In addition, the time until the joint was sheared and broken at a load of 65 ° C. × 392 N (40 kgf) was measured.

(IV) Evaluation of tear strength The tear strength was measured by JISL1096 A-1 method (single tongue method), and the result was evaluated as follows.
○: 250N or more ×: Less than 250N (V) Workability evaluation criteria ○: Tarpaulin can be produced without problems
△: Tarpaulin can be produced with some problems
×: Tarpaulin cannot be produced

Example 1
Preparation of surface film (i) Ethylene-vinyl acetate copolymer resin (Trademark: Evaate CV-2166, MFR1.5, VA content 19% by mass, Sumitomo Chemical Co., Ltd.): 100 parts by mass, and cyclic iminoether group -Containing copolymer resin (trademark: Epocross RPS1005, monomer content containing cyclic iminoether group 5 mass%, Nippon Shokubai Co., Ltd.): Polyolefin resin comprising 5 parts by mass, phosphate ester lubricant (trademark Greg P704A) , Dainippon Ink Co., Ltd.): 2.0 parts by mass, silica (trademark: NIPSEAL AQ, Nippon Silica Industry Co., Ltd.): 10 parts by mass, and pigment (trademark: EV-HS0010, Nichihiro Bix Co., Ltd.) : 5.0 parts by mass, the compound obtained was melt-kneaded for 3 minutes with a Banbury mixer, then two low-temperature set at 140 ° C In 3 minutes homogeneous kneaded, subjecting the kneaded composition to calender rolling molding, to produce 0.28mm thick surface film layer of a (i) film.

Production of Back Film (ii) Ethylene-vinyl acetate copolymer resin (Trademark: Evaate CV-2166, MFR1.5, VA content 19% by mass, Sumitomo Chemical Co., Ltd.): 100 parts by mass, and cyclic iminoether group -Containing copolymer resin (trademark: Epocross RPS1005, monomer content containing cyclic iminoether group 5 mass%, Nippon Shokubai Co., Ltd.): Polyolefin resin comprising 5 parts by mass, phosphate ester lubricant (trademark Greg P704A) , Dainippon Ink Co., Ltd.): 2.0 parts by mass, silica (trademark: NIPSEAL AQ, Nippon Silica Industry Co., Ltd.): 10 parts by mass, and pigment (trademark: PO0907, Nichihiro Bix Co., Ltd.): 5 0.0 parts by mass, the obtained compound was melt-kneaded for 3 minutes with a Banbury mixer, and then 3 minutes with 2 rolls set at 140 ° C. Uniformly kneaded to prepare 0.28mm thick backside film layer of (ii) for the film was subjected to the kneaded composition to calendering molding.

Fabrication of tarpaulin Next, a plain woven fabric woven into 19.0 warps / 25.4mm x 20.0 wefts / 25.4mm with a polyester multifilament of 833 dtex (750 denier) (18% porosity) The surface film (i) and the back film (ii) are heat-laminated by a laminator set at 150 ° C. on each of the front and back surfaces having a mass of 140 g / m ² ), and have a thickness of 0.75 mm and a mass of 680 g / m ^2. A polyolefin resin tarpaulin was produced. The test results are shown in Table 1.

Example 2
In the same manner as in Example 1, a polyolefin resin tarpaulin having a thickness of 0.75 mm and a mass of 680 g / m ² was produced. However, the composition of the polyolefin-based resin for the front and back films was changed to ethylene-vinyl acetate copolymer resin (Trademark: Evertate CV-2166, MFR1.5, VA content 19 mass%, Sumitomo Chemical Co., Ltd.): 70 mass Parts, linear low density ethylene-α-olefin copolymer resin (trademark: Sumikasen FV401, MFR4.0, Sumitomo Chemical Co., Ltd.): 30 parts by weight, cyclic iminoether group-containing copolymer resin (trademark: Epocross) RPS1005, monomer content containing cyclic iminoether group 5 mass%, Nippon Shokubai Co., Ltd.): 5 mass parts. The test results are shown in Table 1.

Example 3
In the same manner as in Example 2, a polyolefin resin tarpaulin having a thickness of 0.75 mm and a mass of 680 g / m ² was produced. However, the amount of cyclic iminoether group-containing copolymer resin (trademark: Epocross RPS1005, monomer content containing cyclic iminoether group, 5% by mass, Nippon Shokubai Co., Ltd.) in the polyolefin resin for front and back films It changed from 5 mass parts to 20 mass parts.

Example 4
In the same manner as in Example 1, a polyolefin resin tarpaulin having a thickness of 0.75 mm and a mass of 680 g / m ² was produced. However, the composition of the polyolefin resin for the front and back films is ethylene-vinyl acetate copolymer resin (trademark: Evaate CV-2166, MFR1.5, VA content 19% by mass, Sumitomo Chemical Co., Ltd.): 70 parts by mass Polypropylene resin alloy (trademark: T-310E, MFR1.5, Idemitsu Petrochemical Co., Ltd.): 30 parts by mass, and cyclic iminoether group-containing copolymer resin (trademark: Epocros RPS1005, monomer containing cyclic iminoether group) The content was changed to 5 parts by mass, Nippon Shokubai Co., Ltd .: 5 parts by mass. The test results are shown in Table 1.

Example 5
In the same manner as in Example 1, a polyolefin resin tarpaulin having a thickness of 0.75 mm and a mass of 680 g / m ² was obtained. However, the composition of the polyolefin-based resin for the front and back films is the same as that of ethylene-methyl methacrylate copolymer resin (trademark: ACRIFTH WH-206, MFR2.0, MMA content 20% by mass, Sumitomo Chemical Co., Ltd.) 100 The mass was changed to 5 parts by mass of a cyclic iminoether group-containing copolymer resin (trademark: Epocross RPS1005, monomer content containing cyclic iminoether group, 5% by mass, Nippon Shokubai Co., Ltd.). The test results are shown in Table 1.

Example 6
In the same manner as in Example 1, a polyolefin resin tarpaulin having a thickness of 0.75 mm and a mass of 680 g / m ² was produced. However, the composition of the polyolefin-based resin for the front and back films is an ethylene-methyl methacrylate copolymer resin (trademark: ACRIFTH WH-206, MFR2.0, MMA content 20% by mass, Sumitomo Chemical Co., Ltd.): 70 parts by mass, linear low-density ethylene-α-olefin copolymer resin (Trademark: Sumikasen FV401, MFR4.0, Sumitomo Chemical Co., Ltd.): 30 parts by mass, and cyclic iminoether group-containing copolymer resin ( Trademark: Epocross RPS1005, monomer content containing cyclic iminoether group 5 mass%, Nippon Shokubai Co., Ltd.): 5 mass parts. The test results are shown in Table 1.

Example 7
In the same manner as in Example 1, a polyolefin resin tarpaulin having a thickness of 0.75 mm and a mass of 680 g / m ² was produced. However, the composition of the polyolefin-based resin for the front and back films is an ethylene-methyl methacrylate copolymer resin (trademark: ACRIFTH WH-206, MFR2.0, MMA content 20% by mass, Sumitomo Chemical Co., Ltd.): 70 parts by mass, polypropylene resin alloy (trademark: T-310E, MFR1.5, Idemitsu Petrochemical Co., Ltd.): 30 parts by mass, cyclic iminoether group-containing copolymer resin (trademark: Epocros RPS1005, containing cyclic iminoether group) The monomer content was changed to 5 mass parts, Nippon Catalysts Co., Ltd .: 5 mass parts. The test results are shown in Table 1.

Example 8
In the same manner as in Example 1, a polyolefin resin tarpaulin having a thickness of 0.75 mm and a mass of 680 g / m ² was produced. However, the composition of the polyolefin-based resin for the front and back films is an ethylene-methyl methacrylate copolymer resin (trademark: ACRIFTH WH-206, MFR2.0, MMA content 20% by mass, Sumitomo Chemical Co., Ltd.): 65 parts by mass, ethylene-methacrylic acid copolymer resin (trademark: Nucrel N0903HC, MFR3.0, MA content 9% by mass, Mitsui DuPont Polychemical Co., Ltd.): 5 parts by mass, linear low density ethylene- α-olefin copolymer resin (trademark: Sumikasen FV401, MFR4.0, Sumitomo Chemical Co., Ltd.): 30 parts by mass, and cyclic iminoether group-containing copolymer resin (trademark: Epocros RPS1005, containing cyclic iminoether group) The monomer content was changed to 5% by mass and 5 parts by mass of Nippon Shokubai Co., Ltd. The test results are shown in Table 1.

Comparative Example 1
Preparation of surface film layer (i) Ethylene-vinyl acetate copolymer resin (Trademark: Evertate CV-2166, MFR1.5, VA content 19% by mass, Sumitomo Chemical Co., Ltd.): polyolefin resin comprising 100 parts by mass In addition, phosphate ester lubricant (trademark Greg P704A, Dainippon Ink Co., Ltd.): 2.0 parts by mass, silica (trademark: NIPSEAL AQ, Nippon Silica Industry Co., Ltd.): 10 parts by mass, and pigment (trademark: EV-HS0010, Nichihiro Bix Co., Ltd.): 5.0 parts by mass was blended. The obtained compound was melt-kneaded with a Banbury mixer for 3 minutes, and then uniformly kneaded with two rolls set at 140 ° C. for 3 minutes. From this kneaded composition, a 0.28 mm-thick surface film layer film ( i) was formed by calendar rolling.
Preparation of surface film layer (ii) Ethylene-vinyl acetate copolymer resin (Trademark: Evertate CV-2166, MFR1.5, VA content 19% by mass, Sumitomo Chemical Co., Ltd.) , Phosphate ester lubricant (Trademark Greg P704A, Dainippon Ink Co., Ltd.): 2.0 parts by mass, Silica (Trademark: NIPSEAL AQ, Nippon Silica Industry Co., Ltd.): 10 parts by mass, and pigment (Trademark: PO0907) , Nihongo Bix Co., Ltd.): 5.0 parts by mass was blended. The obtained compound was melt-kneaded with a Banbury mixer for 3 minutes, and then uniformly kneaded with two rolls set at 140 ° C. for 3 minutes. From this kneaded composition, the back film layer (ii) having a thickness of 0.28 mm was used. The film was formed by calendar rolling.
Fabrication of tarpaulin Next, a plain woven fabric woven into 19.0 warps / 25.4mm x 20.0 wefts / 25.4mm with a polyester multifilament of 833 dtex (750 denier) (18% porosity) The surface film (i) and the back film (ii) are heat-laminated on both sides with a mass of 140 g / m ² ) using a laminator set at 150 ° C., and a polyolefin having a thickness of 0.75 mm and a mass of 680 g / m ² -Based resin tarpaulins were produced. The test results are shown in Table 2.

Comparative Example 2
In the same manner as in Comparative Example 1, a polyolefin resin tarpaulin having a thickness of 0.75 mm and a mass of 680 g / m ² was produced. However, the composition of the polyolefin-based resin for the front and back films was changed to ethylene-vinyl acetate copolymer resin (Trademark: Evertate CV-2166, MFR1.5, VA content 19 mass%, Sumitomo Chemical Co., Ltd.): 70 mass Parts, and linear low density ethylene-α-olefin copolymer resin (trademarks: Sumikasen FV401, MFR4.0, Sumitomo Chemical Co., Ltd.): 30 parts by mass. The test results are shown in Table 2.

Comparative Example 3
In the same manner as in Comparative Example 1, a polyolefin resin tarpaulin having a thickness of 0.75 mm and a mass of 680 g / m ² was produced. However, the composition of the polyolefin-based resin for the front and back films was changed to ethylene-vinyl acetate copolymer resin (Trademark: Evertate CV-2166, MFR1.5, VA content 19 mass%, Sumitomo Chemical Co., Ltd.): 70 mass Parts, and polypropylene resin alloy (trademark: T-310E, MFR1.5, Idemitsu Petrochemical Co., Ltd.): 30 parts by mass. The test results are shown in Table 2.

Comparative Example 4
In the same manner as in Comparative Example 1, a polyolefin resin tarpaulin having a thickness of 0.75 mm and a mass of 680 g / m ² was produced. However, the composition of the polyolefin-based resin for the front and back films is the same as that of ethylene-methyl methacrylate copolymer resin (trademark: ACRIFTH WH-206, MFR2.0, MMA content 20% by mass, Sumitomo Chemical Co., Ltd.) 100 Changed to parts by mass. The test results are shown in Table 2.

Comparative Example 5
In the same manner as in Comparative Example 1, a polyolefin resin tarpaulin having a thickness of 0.75 mm and a mass of 680 g / m ² was produced. However, the composition of the polyolefin resin for the front and back films is ethylene-methyl acrylate copolymer resin (trademark: ACRIFTH WH-206, MFR2.0, MMA content 20% by mass, Sumitomo Chemical Co., Ltd.): 70 Mass parts and linear low density ethylene-α-olefin copolymer resin (trademarks: Sumikasen FV401, MFR4.0, Sumitomo Chemical Co., Ltd.): 30 parts by mass. The test results are shown in Table 2.

Comparative Example 6
In the same manner as in Comparative Example 1 was prepared a thickness 0.75 mm, mass 680 g / m ² of polyolefin resin tarpaulin. However, the composition of the polyolefin-based resin for the front and back films was changed to ethylene-methyl acrylate copolymer resin (trademark: ACRIFTH WH-206, MFR2.0, MMA content 20% by mass, Sumitomo Chemical Co., Ltd.): 65 Parts by mass, ethylene-methacrylic acid copolymer resin (trademark: Nucrel N0903HC, MFR3.0, MA content 9% by mass, Mitsui DuPont Polychemical Co., Ltd.): 5 parts by mass, and linear low density ethylene- α-olefin copolymer resin (Trademarks: Sumikasen FV401, MFR4.0, Sumitomo Chemical Co., Ltd.): Changed to 30 parts by mass. The test results are shown in Table 2.

Comparative Example 7
In the same manner as in Comparative Example 1, a polyolefin resin tarpaulin having a thickness of 0.75 mm and a mass of 680 g / m ² was produced. However, the composition of the polyolefin-based resin for the front and back films is an ethylene-methyl methacrylate copolymer resin (trademark: ACRIFTH WH-206, MFR2.0, MMA content 20% by mass, Sumitomo Chemical Co., Ltd.): 70 parts by mass and polypropylene resin alloy (trademark: T-310E, MFR1.5, Idemitsu Petrochemical Co., Ltd.): The blend resin was changed to 100 parts by mass.

Comparative Example 8
In the same manner as in Example 2, a polyolefin resin tarpaulin having a thickness of 0.75 mm and a mass of 680 g / m ² was produced. However, the amount of cyclic iminoether group-containing copolymer resin (trademark: Epocros RPS1005, monomer content containing cyclic iminoether group 5 mass%, Nippon Shokubai Co., Ltd.) was changed from 5 mass parts to 25 mass parts. did. Although the front and back film layers could be formed using the polyolefin-based resin, a tarpaulin having a high melt viscosity and a rough surface was obtained. The test results are shown in Table 2.

Comparative Example 9
The front and back films were calendered using the same resin as in Example 2. However, the amount of cyclic iminoether group-containing copolymer resin (trademark: Epocros RPS1005, monomer content containing cyclic iminoether group 5 mass%, Nippon Shokubai Co., Ltd.) was changed from 5 mass parts to 30 mass parts. . In film formation of the obtained polyolefin resin, the film could not be peeled off from the calender roll due to adhesion of the resin to the calender roll. The test results are shown in Table 2.

Comparative Example 10
An attempt was made to melt knead a polyolefin resin for front and back films having the same resin composition as in Example 2. However, 5 parts by mass of the cyclic iminoether group-containing copolymer resin (trademark: Epocross RPS1005, Nippon Shokubai Co., Ltd.) was changed to 10 parts by mass of an isocyanate compound (trademark: Coronate L, Nippon Polyurethane Industry Co., Ltd.). This resin could not be uniformly kneaded and could not be formed into a film. The test results are shown in Table 2.

Comparative Example 11
In the same manner as in Comparative Example 2, a polyolefin resin tarpaulin having a thickness of 0.75 mm and a mass of 700 g / m ² was produced. However, as a fibrous base fabric, an 833 dtex (750 denier) polyester multifilament yarn was used and a plain weave woven to warp density: 19.0 / 25.4 mm × weft density: 20.0 / 25.4 mm A woven fabric (porosity 18%, basis weight 140 g / m ² ), urethane emulsion (trademark: Permusen WF-41-083, solid content 40%, Star Japan Co., Ltd.) 100 parts by mass, aziridine crosslinking agent 10 What performed the adhesion process using the adhesion processing composition which consists of a mass part and 50 mass parts of distilled water was used. The test results are shown in Table 2.

  In Tables 1 and 2, from the results of Examples 1, 2, and 4-8 and Comparative Examples 1-7, the flexibility of the tarpaulin obtained by adding a cyclic iminoether group-containing copolymer resin to the polyolefin resin layer It was confirmed that the heat-resistant creep resistance was dramatically improved without adversely affecting the workability, high-frequency welder sewability and tear strength. Regarding the addition amount of the cyclic iminoether group-containing copolymer resin, as apparent from Examples 2, 3 and Comparative Examples 8 and 9, the effect of improving the heat-resistant creep property is increased by increasing the addition amount, When the added amount exceeded 20 parts by mass, the effect was saturated and no change was observed, while the tendency for flexibility and workability to decrease was observed. From Examples 2, 4, 6, 7, and 8 and Comparative Examples 2, 3, 5, and 6, a polyolefin resin such as a linear low density ethylene-α-olefin copolymer resin and a polypropylene resin alloy is further blended. As a result, the heat resistance creep resistance was improved, although the flexibility was slightly impaired. Although only a blend of these blend component resins provides a small effect, the heat creep resistance is remarkably improved by using this blend component resin together with the cyclic imino ether group-containing copolymer resin. In Comparative Example 10, addition of an isocyanate compound was attempted, but kneading with a polyolefin resin could not be performed well, and a tarpaulin could not be produced. In Comparative Example 11, as the fibrous base fabric, a polyester multifilament plain woven fabric that was subjected to adhesion treatment with an adhesive obtained by adding an aziridine-based crosslinking agent to a urethane-based emulsion was used. Although the same effect as the Example was shown, the result that flexibility and tear strength were impaired was recognized.

  The polyolefin resin tarpaulin obtained by the present invention has an excellent heat-resistant creep property, and, for example, what is heat-sealed by using the tarpaulin of the present invention has a heat-resistant creep property at the joint. It became possible to meet the condition of 60 ° C. × 392 N (40 kgf) load × 24 hours or more, which was conventionally considered difficult. Therefore, by using the polyolefin-based resin tarpaulin of the present invention as a raw material for a flexible container for transporting raw materials, the flexible container is thermally deformed even when filled with a raw material having a temperature of about 50 to 60 ° C., or the flexible container itself There is less concern about the destruction of the container than before, which makes it possible to increase the efficiency of flexible container logistics in various raw material manufacturers.

Claims (5)

A fibrous base fabric and a membrane material including a polyolefin-based resin layer laminated on both front and back surfaces,
The polyolefin resin composition forming the polyolefin resin layer is (a) as its main resin component,
An ethylene-based copolymer resin composed of at least one selected from an ethylene-vinyl acetate copolymer resin and an ethylene- (meth) acrylic acid (ester) copolymer resin, and (b) a heat-resistant creep resistance improving component. Including 0.5 to 20 parts by mass of a cyclic iminoether group-containing copolymer resin with respect to 100 parts by mass of the main resin component (a),
A polyolefin resin tarpaulin with excellent heat-resistant creep properties.   The polyolefin resin composition comprises (c) an additional polyolefin resin comprising at least one selected from a polyethylene resin, an ethylene-α-olefin copolymer resin, and a polypropylene resin alloy as an additional blend component, The polyolefin resin tarpaulin excellent in heat-resistant creep property according to claim 1, which is contained in a proportion of 70% by mass or less with respect to the main component resin (a).   In the main resin component of the polyolefin resin composition, the total mass of vinyl acetate and (meth) acrylic acid (ester) contained as a comonomer is the mass of the main resin component (a), or the main resin. The polyolefin resin tarpaulin excellent in heat-resistant creep property according to claim 1 or 2, wherein the content is 5 to 30% by mass relative to the total mass of the component (a) and the additional blend component (c).   The crosslinked structure by ring-opening of the said cyclic iminoether group containing copolymer resin is formed in the lamination | stacking interface of the said polyolefin-type resin layer and the said fibrous base fabric layer in any one of Claims 1-3. A polyolefin resin tarpaulin with excellent heat-resistant creep resistance as described. The polyolefin resin excellent in heat-resistant creep property according to any one of claims 1 to 4, wherein the cyclic iminoether group-containing copolymer resin has an oxazoline group represented by the following chemical formula (1). Tarpaulin.