JP6943819B2 - Conveyance belt - Google Patents

Description

The present invention relates to an endless conveyor belt used in a belt conveyor device.

Conventionally, as a conveyor belt used in a belt conveyor device, as shown in FIG. 1, a flat belt having a two-layer structure in which a core canvas 1 and a resin layer (cover layer) 3 are laminated is known. Such a transport belt is used in an endless manner by cutting a long laminated sheet to a predetermined length and joining both ends thereof.

In the transport belt, the cover layer, which is the surface (transport surface) on which the transported object is loaded and transported, is appropriately selected and used as the optimum resin material in order to correspond to the type of the transported object and the usage environment. For example, as the resin material used for the cover layer, a thermoplastic elastomer (or thermoplastic resin) such as urethane-based, vinyl chloride (PVC) -based, or olefin-based is used. Further, in order to ensure the adhesiveness between the cover layer and the core canvas, the core canvas is a canvas that has been subjected to an adhesive treatment and has an adhesive component adhered to the adhesive surface.

A transport belt having a cover layer made of an olefin-based material such as an olefin-based elastomer or an olefin-based resin is superior in non-adhesiveness and stain resistance to a transport belt having a cover layer made of a urethane-based elastomer. Therefore, it can be suitably used in fields such as food transportation. However, on the other hand, the olefin-based material is a poorly adhesive material, and the cover layer formed of the olefin-based material ensures adhesiveness to the core canvas as compared with the cover layer formed of the urethane-based elastomer. There was a drawback that it was difficult to do. Therefore, a technique for improving the adhesiveness between the cover layer made of an olefin-based material and the core canvas has been studied.

Japanese Patent Application Laid-Open No. 10-272704 (Patent Document 1), Japanese Patent Application Laid-Open No. 10-278129 (Patent Document 2), Japanese Patent Application Laid-Open No. 11-59842 (Patent Document 3), and Japanese Patent Application Laid-Open No. 11-59843 (Patent Document 4). ) Is a conveyor belt in which a resin layer and a fiber canvas are laminated. The resin layer is made of an acid anhydride copolymer polyolefin, and the fiber canvas is an ethylene-vinyl acetate copolymer / carboxylation modification. A conveyor belt treated with an adhesive consisting of an ethylene-vinyl acetate copolymer, a thermoplastic polyurethane resin, a solvent-soluble polyester resin, or an epoxy resin is disclosed. In these conveyor belts, the olefin resin in the resin layer is modified and various adhesive treatments are applied to the core canvas to improve the adhesiveness between the core canvas and the cover layer formed of the olefin material. There is.

However, even with these conveyor belts, the adhesive strength between the core canvas and the cover layer was not sufficient. Further, the cover layer made of a polyolefin-based material has another problem that cracks are likely to occur due to repeated bending during use.

Regarding cracks in the cover layer formed of a polyolefin-based material, Japanese Patent Application Laid-Open No. 2006-8378 (Patent Document 5) describes a conveyor belt having improved flexibility of the cover layer formed of a polyolefin-based resin in which cracks are likely to occur. Disclosed as a resin conveyor belt having a cover layer formed of a thermoplastic polyolefin resin and a multi-layered graft copolymer containing a fatty acid amide. It is stated that this conveyor belt has excellent non-adhesiveness, abrasion resistance and stain resistance.

However, this document does not describe the adhesiveness between the cover layer and the core body. As described above, in the conventional technique, the transport belt having the cover layer made of the polyolefin-based material cannot achieve both the adhesiveness between the cover layer and the core canvas and the crack resistance of the cover layer at a high level. ..

JP-A-10-272704 (Claim 1) Japanese Patent Application Laid-Open No. 10-278129 (Claim 1) JP-A-11-59842 (Claim 1) JP-A-11-59843 (Claim 1) JP-A-2006-8378 (Claim 1, paragraphs [0009] [0016])

An object of the present invention is a transport belt having high adhesiveness between the cover layer and the core body and high crack resistance of the cover layer even if the cover layer is formed of a polyolefin-based material having excellent non-adhesiveness and stain resistance. Is to provide.

As a result of diligent studies to achieve the above problems, the present inventors have made a thermoplastic olefin polymer and a thermoplastic amorphous polymer between the cover layer formed of the polyolefin-based material and the core including the cloth. Even if the cover layer is formed of a polyolefin-based material having excellent non-adhesiveness and stain resistance by interposing an adhesive layer containing a polymer alloy with the above, the adhesiveness between the cover layer and the core and the resistance of the cover layer The present invention has been completed by finding that the crack property can be improved.

That is, the transport belt of the present invention is laminated on the first core body including the cloth, the first adhesive layer laminated on the outer peripheral surface side of the first core body, and the first adhesive layer, and is conveyed. A transport belt including an outer peripheral cover layer forming a surface, wherein the first adhesive layer contains a polymer alloy of a thermoplastic olefin polymer and a thermoplastic amorphous polymer, and the outer peripheral cover layer is thermally generated. Includes thermoplastic olefin-based polymers. The thermoplastic amorphous polymer of the first adhesive layer is at least one selected from the group consisting of a thermoplastic styrene polymer, a thermoplastic vinyl chloride polymer, a thermoplastic (meth) acrylic polymer, and a thermoplastic urethane polymer. It may be a seed. The thermoplastic olefin-based polymer of the outer peripheral cover layer and the first adhesive layer may contain a polyethylene-based resin. The first core body may further contain a thermoplastic amorphous polymer. In the first adhesive layer, the mass ratio of the thermoplastic olefin polymer and the thermoplastic amorphous polymer may be about 80/20 to 20/80 of the former / the latter. The average thickness of the outer peripheral cover layer may be about 0.05 to 1 mm. The average thickness of the first adhesive layer may be about 0.05 to 1 mm. The transport belt of the present invention is laminated on the inner peripheral surface side of the first core body and contains a second adhesive layer containing a thermoplastic amorphous polymer, and is laminated on the second adhesive layer and contains a cloth. The second core body may be further included. Further, the transport belt of the present invention has a third adhesive layer laminated on the inner peripheral surface side of the first core body and containing a polymer alloy of a thermoplastic olefin polymer and a thermoplastic amorphous polymer, and a third adhesive layer thereof. It may further include an inner peripheral cover layer laminated on the adhesive layer and containing a thermoplastic olefin polymer.

In the present specification and claims, "thermoplastic polymer" is used in the sense of including a thermoplastic resin and a thermoplastic elastomer.

In the present invention, an adhesive layer containing a polymer alloy of a thermoplastic olefin polymer and a thermoplastic amorphous polymer is interposed between a cover layer formed of a polyolefin-based material and a core body containing a cloth. Therefore, even if the cover layer is formed of a polyolefin-based material having excellent non-adhesiveness (removability) and stain resistance, the adhesiveness between the cover layer and the core and the crack resistance of the cover layer can be improved.

FIG. 1 is a schematic view showing a conventional transport belt. FIG. 2 is a schematic view showing an example of the transport belt of the present invention. FIG. 3 is a schematic view showing another example of the transport belt of the present invention. FIG. 4 is a schematic view showing still another example of the transport belt of the present invention. FIG. 5 is a side view of the transport belt of the present invention prepared in an endless shape and mounted on a pulley. FIG. 6 is a plan view of a joint portion of the transport belt of the present invention prepared in an endless shape. FIG. 7 is a schematic view showing the measurement points of the belt obtained in the examples in the adhesive force measurement of the examples. FIG. 8 is a schematic view showing the measurement points of the belts obtained in the comparative example in the adhesive force measurement of the examples. FIG. 9 is a schematic view showing a schematic layout of the 5-axis running tester used in the running test of the embodiment.

[Convey belt]
In the transport belt of the present invention, an adhesive layer containing a polymer alloy of a thermoplastic olefin polymer and a thermoplastic amorphous polymer is provided between a core body containing a cloth and an outer peripheral cover layer containing a thermoplastic olefin polymer. It suffices to have an intervening three-layer structure, and in addition to these three layers, another core body, an inner peripheral cover layer, or the like may be provided.

FIG. 2 is a schematic view showing an example of a transport belt having a three-layer structure of the present invention, in which the first core body 1 and the first adhesive layer 2 laminated on the outer peripheral surface side of the first core body 1 are It is formed by an outer peripheral cover layer 3 that is laminated on the first adhesive layer 2 and forms a transport surface. In this transport belt, the first core body 1 containing the cloth and the outer peripheral cover layer containing the thermoplastic olefin polymer contain a polymer alloy of the thermoplastic olefin polymer and the thermoplastic amorphous polymer. By interposing the adhesive layer, the adhesiveness between the first core body and the outer peripheral cover layer and the crack resistance of the outer peripheral cover layer are improved.

Further, FIG. 3 is a schematic view showing another example of the transport belt of the present invention, which is laminated on the inner peripheral surface side of the first core body 1 with respect to the transport belt having the three-layer structure shown in FIG. The second adhesive layer 4 and the second core body 5 laminated on the second adhesive layer 4 are further formed. In this transport belt, a second core body 5 including a cloth is laminated on the inner peripheral surface side of the first core body 1 via a second adhesive layer 4 containing a thermoplastic amorphous polymer, and a plurality of cores are laminated. By forming a five-layer structure having a body, it can be used with high tension and durability can be improved.

Further, FIG. 4 is a schematic view showing another example of the transport belt of the present invention, which is laminated on the inner peripheral surface side of the first core body 1 with respect to the transport belt having the three-layer structure shown in FIG. A third adhesive layer 6 and an inner peripheral cover layer 7 laminated on the third adhesive layer 6 are further formed. In this transport belt, a thermoplastic olefin polymer is placed on the inner peripheral surface side of the first core body 1 via a third adhesive layer 6 containing a polymer alloy of a thermoplastic olefin polymer and a thermoplastic amorphous polymer. The durability of the transport belt can be further improved by laminating the inner peripheral cover layer 7 including the inner peripheral cover layer 7 to form a five-layer structure having the inner peripheral cover layer also on the inner peripheral surface. For example, it is possible to prevent the spilled material from adhering to the inner surface of the belt and shortening the life of the belt.

The transport belt of the present invention may have at least the three-layer structure shown in FIG. 2, and is not limited to the embodiment shown in FIGS. 2 to 4. The transport belt of the present invention is, for example, a transport belt in which three or more core bodies are laminated via an adhesive layer, or a transport belt in which two or more core bodies and an inner peripheral cover layer are laminated via an adhesive layer. And so on.

(First adhesive layer)
The first adhesive layer contains a polymer alloy of a thermoplastic olefin polymer and a thermoplastic amorphous polymer. In the present invention, by including such a polymer alloy, the first adhesive layer can firmly bond the first core body formed of different materials and the outer peripheral cover layer, and suppress the occurrence of cracks in the cover layer. can. Further, since the occurrence of cracks can be suppressed, the applicable range of the transport belt (high tension, small pulley diameter) is widened. On the other hand, in the conventional transport belt, a non-uniform stress acts on the cover layer and cracks are likely to occur. In the transport belt of the present invention, the mechanism by which cracks in the cover layer can be suppressed can be estimated as follows. That is, in the transport belt of the present invention, since the cover layer is laminated on a substantially flat adhesive layer, it is not so affected by the unevenness of the surface of the fabric such as canvas, and is a polyolefin-based material in which cracks are likely to occur in terms of material. It can be presumed that the occurrence of cracks is suppressed even if the cover layer is formed with. Further, probably because the polymer alloy can achieve both flexibility and mechanical strength, it is possible to suppress the occurrence of cracks in the adhesive layer itself while following the uneven shape of the cloth surface.

(1) Thermoplastic Olefin Polymer The thermoplastic olefin polymer may be an olefin resin or an olefin elastomer.

The olefin resin is a single or copolymer containing α-olefin as a constituent unit. Examples of α-olefins include ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-butene, 1-hexene and 1-hexene. Examples thereof include α-C _{2-10 olefins such as octene.} These α-olefins can be used alone or in combination of two or more. Among these α- olefins, ethylene, _{alpha-C 2-4} olefin such as propylene (especially, _{alpha-C 2-3} olefin such as ethylene) is preferred.

The olefin resin may contain a copolymerizable monomer in addition to the α-olefin as a constituent unit. Examples of the copolymerizable monomer include unsaturated monocarboxylic acids [eg, (meth) acrylic acid, crotonic acid, etc.], unsaturated monocarboxylic acid esters [eg, methyl (meth) acrylate, ethyl (meth) acrylate, etc.]. _{, (Meta) acrylic acid C 1-6} alkyl esters such as butyl (meth) acrylic acid], unsaturated dicarboxylic acids or anhydrides thereof [eg, (anhydrous) maleic acid, fumaric acid, (anhydrous) citraconic acid, (anhydrous) ) Acrylic acid, etc.], vinyl esters (eg, vinyl acetate, vinyl propionate, etc.), cyclic olefins (norbornen, etilidennorbornene, cyclopentene, cyclopentadiene, cyclohexene, etc.), dienes (butadiene, isoprene, 1,4- (Pentazien, etc.) and the like. These copolymerizable monomers can be used alone or in combination of two or more. Among these copolymerizable monomers, unsaturated monocarboxylic acids, unsaturated dicarboxylic acid anhydrides, vinyl esters and the like are preferable.

The ratio of the copolymerizable monomer is, for example, 0 to 50 mol (for example, 0.01 to 50 mol), preferably 0 to 30 mol (for example, 0.1 to 30 mol), more preferably 0 to 30 mol, based on 100 mol of the α-olefin. May be about 0 to 10 mol.

Examples of the olefin resin include polyolefins (low, medium or high density polyethylene, polyethylene such as linear low density polyethylene, ethylene-propylene copolymer, polypropylene such as atactic polypropylene, polybutene, and propylene-butene-1). Polymers, ethylene-propylene-butene-1 copolymers, poly4-methyl-1-pentene, etc.) and the like. These olefin resins can be used alone or in combination of two or more.

The olefin-based elastomer may be an elastomer in which the olefin-based resin such as polyethylene or polypropylene has a hard segment (hard phase) and the rubber component has a soft segment (soft phase). Examples of the rubber component constituting the soft segment include ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), ethylene-α-olefin copolymer, natural rubber (NR), and nitrile rubber (NBR). Examples include hydrogenated isoprene rubber. These olefin-based elastomers can be used alone or in combination of two or more.

The thermoplastic olefin polymer may be a combination of the olefin resin and the olefin elastomer.

Among these thermoplastic olefin-based polymers, polyethylene-based resin and polyethylene-based elastomer are preferable from the viewpoint of durability such as interlayer adhesion and crack resistance, and low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) are preferable. ) And other polyethylene-based resins (particularly, polyethylene-based resins having a low density) are particularly preferable.

The density of the thermoplastic olefin polymer (particularly, polyethylene resin) ^{can be selected from the range of about 0.8 to 0.97 g / cm 3} by a method based on ASTM D792, for example, 0.82 to 0.95 g /. It is about cm ³ , preferably 0.85 to 0.93 g / cm ³ , and more preferably about 0.88 to 0.92 g / cm ³ (particularly 0.89 to ^{0.91 g / cm 3} ). If the density is too low, the durability and releasability (or stain resistance) of the transport belt may decrease, and if it is too large, the adhesiveness may decrease.

The melt mass flow rate (MFR) of a thermoplastic olefin polymer (particularly a polyethylene resin) is, for example, 0.1 to 30 g / 10 minutes, preferably 1 to 10 g / 10 minutes, and further, in a measurement method based on JIS K7210. It is preferably about 3 to 8 g / 10 minutes (particularly 4 to 6 g / 10 minutes). If the MFR is too small, the adhesiveness may decrease, and if it is too large, the durability and releasability of the transport belt may decrease.

The crystallinity of the thermoplastic olefin polymer (particularly polyethylene resin) is, for example, about 30 to 95%, preferably 40 to 90%, and more preferably 50 to 70% (particularly 55 to 60%). If the crystallinity is too small, the durability and releasability of the transport belt may decrease, and if it is too large, the adhesiveness may decrease. The crystallinity can be measured by a conventional method by X-ray diffraction.

(2) Thermoplastic Amorphous Polymer Examples of the thermoplastic amorphous polymer include a thermoplastic styrene polymer, a thermoplastic vinyl chloride polymer, a thermoplastic (meth) acrylic polymer, and a thermoplastic urethane polymer. Be done. These amorphous polymers can be used alone or in combination of two or more. Of these, thermoplastic vinyl chloride-based polymers and thermoplastic urethane-based polymers are preferable, and thermoplastic urethane-based polymers (thermoplastic urethane-based elastomers) are particularly preferable.

(2-1) Thermoplastic Styrene-based Polymer The thermoplastic styrene-based polymer may be a styrene-based resin or a styrene-based elastomer.

Examples of the styrene resin include polystyrene, styrene-methyl methacrylate copolymer (MS resin), acrylonitrile-styrene copolymer (AS resin), acrylonitrile-styrene-methyl methacrylate copolymer, and acrylonitrile-butadiene-styrene. Examples thereof include a copolymer (ABS resin) and rubber-reinforced polystyrene (HIPS). These styrene resins can be used alone or in combination of two or more.

The styrene-based elastomer is an elastomer having the above-mentioned styrene-based resin such as polystyrene as a hard segment and rubber components such as (hydrogenated) butadiene rubber, (hydrogenated) isoprene rubber, and (hydrogenated) styrene-butadiene rubber as a soft segment. There may be. These styrene-based elastomers can be used alone or in combination of two or more.

Among these thermoplastic styrene-based polymers, polystyrene, ABS resin and the like are widely used.

(2-2) Thermoplastic Vinyl Chloride Polymer The thermoplastic vinyl chloride polymer may be a vinyl chloride resin or a vinyl chloride elastomer.

Examples of the vinyl chloride resin include polyvinyl chloride, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-vinyl acetate copolymer, and vinyl chloride-C _2-4 olefin copolymer (vinyl chloride-ethylene copolymer). , Vinyl chloride-propylene copolymer, etc.), vinyl chloride- (meth) acrylic acid ester copolymer (vinyl chloride-methyl methacrylate copolymer, etc.), vinyl chloride-acrylonitrile copolymer, etc.

These vinyl chloride resins may be soft vinyl chloride resins containing a plasticizer. Examples of the plasticizer include phthalate ester-based plasticizers, phosphoric acid ester-based plasticizers, aliphatic polyvalent carboxylic acid esters, epoxy-based plasticizers, and the like. These plasticizers can be used alone or in combination of two or more. The ratio of the plasticizer can be selected from the range of about 1 to 150 parts by mass with respect to 100 parts by mass of the vinyl chloride resin, for example, 10 to 100 parts by mass, preferably 20 to 90 parts by mass, and more preferably 30 to 80 parts by mass. It may be about a part.

The vinyl chloride-based elastomer uses the vinyl chloride-based resin such as highly polymerizable polyvinyl chloride or crosslinked polyvinyl chloride as a hard segment, and soft vinyl chloride such as soft polyvinyl chloride (hydrogenated) or nitrile rubber-containing polyvinyl chloride. It may be an elastomer having a soft segment of a based resin. These vinyl chloride elastomers can be used alone or in combination of two or more.

Among these thermoplastic vinyl chloride-based polymers, polyvinyl chloride, soft polyvinyl chloride, and the like are widely used.

(2-3) Thermoplastic (meth) acrylic polymer Examples of the thermoplastic (meth) acrylic polymer include poly (meth) acrylic acid esters such as polymethyl methacrylate and methyl methacrylate- (meth) acrylic acid. Polymer, methyl methacrylate- (meth) acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester- (meth) acrylic acid copolymer, (meth) acrylic acid- (meth) methyl acrylate- (meth) Examples thereof include isobornyl acrylate copolymers. These thermoplastic (meth) acrylic polymers can be used alone or in combination of two or more. Of these, poly (meth) acrylate C _1-6 alkyl such as methyl poly (meth) acrylate is widely used.

(2-4) Thermoplastic Urethane Polymer The thermoplastic urethane polymer may be a polyurethane obtained by reacting polyols with polyisocyanates.

Examples of the polyols include polyester polyols, polyether polyols, polyether ester polyols, polycarbonate polyols, polyesteramide polyols, acrylic polymer polyols and the like. These polyols can be used alone or in combination of two or more. Among these polyols, polyether polyols (poly C _2-4 alkylene glycol such as polyethylene glycol and polytetramethylene glycol ether) and polycarbonate polyols (ethylene glycol and 1, Reaction products of diols such as 4-butanediol and diC _{1-4 alkyl carbonates such as dimethyl carbonate or diC 6-12} aryl carbonates such as diphenyl carbonate) are preferred.

Polyisocyanates include, for example, aliphatic diisocyanates such as aliphatic polyisocyanates [propylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMDI), lysine diisocyanate (LDI), etc. , 1,6,11-Undecantryisocyanate Methyloctane, 1,3,6-hexamethylene triisocyanate and other aliphatic triisocyanates], alicyclic polyisocyanate [cyclohexane 1,4-diisocyanate, isophorone diisocyanate (IPDI), Hydrocyclic diisocyanates such as hydrogenated xylylene diisocyanate and hydrogenated bis (isocyanatophenyl) methane, alicyclic triisocyanates such as bicycloheptane triisocyanate], aromatic polyisocyanates [phenylenediocyanate, tolylene diisocyanate (TDI) ), Xylylene diisocyanate (XDI), Tetramethylxylylene diisocyanate (TMXDI), Naphthalene diisocyanate (NDI), Bis (isocyanatophenyl) methane (MDI), Truisidine diisocyanate (TODI), 1,3-bis (isocyanatophenyl) ) Aromatic diisocyanates such as propane] and the like are included.

These polyisocyanates include derivatives such as multimers (dimers, trimers, tetramers, etc.), adducts, modified products (biuret modified products, alohanate modified products, urea modified products, etc.), and a plurality of polyisocyanates. It may be a urethane oligomer having an isocyanate group or the like.

These polyisocyanates can be used alone or in combination of two or more. Among these polyisocyanates, aliphatic diisocyanates such as HDI, alicyclic diisocyanates such as IPDI, aromatic aliphatic diisocyanates such as XDI, and aromatic diisocyanates such as MDI and TDI are widely used and are highly versatile. Aromatic diisocyanates are particularly preferred.

Among these thermoplastic urethane-based polymers, polyether-type polyurethane and polycarbonate-type polyurethane are preferable, and polyether-type polyurethane (polyether-type urethane elastomer) is particularly preferable, from the viewpoint of excellent water resistance and chemical resistance.

(3) Characteristics of First Adhesive Layer The mass ratio of the thermoplastic olefin polymer of the first adhesive layer to the thermoplastic amorphous polymer of the first adhesive layer is, for example, the former / the latter = 80/20 to 20/80. It is preferably about 78/22 to 30/70 (for example, 75/25 to 50/50), and more preferably about 73/27 to 60/40 (particularly 72/28 to 65/35). If the proportion of the thermoplastic olefin polymer is too small, the adhesiveness to the core body is improved, but the adhesiveness to the outer peripheral cover layer may be lowered. On the contrary, if the proportion is too large, the adhesiveness to the outer peripheral cover layer is improved. However, there is a risk that the adhesiveness with the core body will decrease. In particular, a large proportion of the thermoplastic olefin polymer is preferable from the viewpoint of crack resistance, and the proportion of the thermoplastic olefin polymer may be 50% by mass or more.

In addition to the thermoplastic olefin polymer and the thermoplastic amorphous polymer, the first adhesive layer is composed of conventional additives such as stabilizers (weather stabilizers, antioxidants, thermal stabilizers, light stabilizers, etc.). It may contain fillers, plasticizers, lubricants, colorants, solvents and the like. These additives can be used alone or in combination of two or more. The ratio of the additive is 30 parts by mass or less, preferably 0.1 to 20 parts by mass, and more preferably about 1 to 15 parts by mass with respect to 100 parts by mass of the total of the thermoplastic olefin polymer and the thermoplastic amorphous polymer. Is.

The ratio of the polymer component (total of the thermoplastic olefin polymer and the thermoplastic amorphous polymer) in the first adhesive layer may be 50% by mass or more, preferably 80% by mass or more, and more preferably 90% by mass. As mentioned above, it may be 100% by mass (only the polymer component).

The average thickness of the first adhesive layer can be selected from the range of about 0.05 to 1.5 mm (particularly 0.05 to 1.2 mm), for example, 0.05 to 1 mm, preferably 0.1 to 0.5 mm, and further. It is preferably about 0.13 to 0.3 mm (particularly 0.15 to 0.25 mm). If the average thickness of the first adhesive layer is too thin, the crack resistance may decrease, and if it is too thick, the durability such as crack resistance decreases or the flexibility decreases, and a small diameter pulley is used. May be difficult to use.

(1st core body)
The first core body may contain a cloth. As the cloth (or canvas), a cloth commonly used for the core body of the transport belt can be used, and examples thereof include woven cloth and knitted cloth. Of these fabrics, woven fabrics are preferable because they are excellent in strength and productivity.

The woven structure (woven structure) of the woven fabric may be, for example, a plain weave, a twill weave (oblique weave), a satin weave (satin weave), or the like. Among these woven structures, a plain weave may be used from the viewpoint of excellent balance of strength and the like, and a twill weave and a satin weave structure may be used from the viewpoint of adhesion to the first adhesive layer.

In the woven fabric, the density of the warp threads is, for example, 10 to 150 threads / 5 cm, preferably 30 to 120 threads / 5 cm, and more preferably about 60 to 100 threads / 5 cm. The density of the weft is, for example, 10 to 120 threads / 5 cm, preferably 30 to 100 threads / 5 cm, and more preferably about 50 to 90 threads / 5 cm.

The form of the yarn (warp and weft) forming the woven fabric is not particularly limited, and is a multifilament yarn in which a plurality of filaments (long fibers) are aligned or twisted, one long fiber, a monofilament yarn, and a short fiber. It may be any spun yarn (spun yarn) in which fibers are twisted. When the warp or weft is a multifilament yarn or a spun yarn, it may be a blended yarn, a blended yarn, or a blended yarn using fibers of a plurality of materials.

Fibers of various materials can be used as the fibers forming the threads, for example, polyester fibers (polyalkylene allylate fibers such as polyethylene terephthalate and polyethylene naphthalate), polyamide fibers (aliphatic polyamide fibers such as polyamide 6 and polyamide 66, etc.). (Aramid fiber, etc.), cellulose-based fiber such as cotton or rayon, etc. may be used. _{Of these, poly C 2-4} alkylene arylate fibers such as polyethylene terephthalate (PET) are preferable from the viewpoint of excellent balance of strength and flexibility.

The thickness (total fineness) of the yarn is, for example, 100 to 1200 dtex, preferably 300 to 1000 dtex, and more preferably about 500 to 800 dtex. The yarn may be formed of a single yarn, or may be a twisted (or combined) yarn of a plurality of yarns. The number of raw yarns to be twisted (or combined) is not particularly limited, and is, for example, 2 to 12, preferably 2 to 6, and more preferably about 2 to 3. The raw yarn may be a multifilament yarn, a monofilament yarn, or a spun yarn.

The average thickness of the fabric is, for example, 0.2 to 2.0 mm, preferably 0.2 to 1.0 mm, and more preferably about 0.3 to 0.7 mm.

The first core body may be impregnated with a resin component between the fibers inside the fabric from the viewpoint of improving the adhesiveness with the first adhesive layer. As the resin component, the amorphous polymer exemplified as the thermoplastic amorphous polymer of the first adhesive layer can be used alone or in combination of two or more. Among the amorphous polymers, a polymer of the same type (particularly the same) as the thermoplastic amorphous polymer of the first adhesive layer is preferable from the viewpoint of improving the adhesion to the first adhesive layer. Therefore, when the thermoplastic amorphous polymer of the first adhesive layer is a thermoplastic urethane-based polymer, the resin component of the core is preferably a thermoplastic urethane-based polymer. As the thermoplastic urethane-based polymer, the polyurethane exemplified as the thermoplastic urethane-based polymer in the thermoplastic amorphous polymer of the first adhesive layer can be used alone or in combination of two or more. Of the polyurethanes, a polyether type polyurethane or a polycarbonate type polyurethane is preferable for the same reason as the first adhesive layer.

The ratio of the resin component is, for example, about 10 to 100 parts by mass, preferably about 10 to 50 parts by mass with respect to 100 parts by mass of the fabric. If the proportion of the resin component is too small, the strength may be insufficient and the adhesion to the first adhesive layer may be lowered, and if it is too large, the flexibility required for the belt may be lowered.

When the resin component is a thermoplastic urethane-based polymer, it may be combined with a curing agent. As the curing agent, conventional curing agents such as polyisocyanates, polyols, and polyamines can be used and can be selected according to the type of polyurethane, but polyisocyanates are preferable from the viewpoint of reactivity and the like. As the polyisocyanates, the polyisocyanates can be used. Among the polyisocyanates, aromatic diisocyanates are preferable as the curing agent from the viewpoint of stable reactivity. The ratio of the curing agent is, for example, 1 to 50 parts by mass, preferably 2 to 25 parts by mass, and more preferably 5 to 10 parts by mass with respect to 100 parts by mass of the thermoplastic urethane polymer.

The first core may also contain the conventional additives exemplified in the section of the first adhesive layer. The ratio of the additive is 30 parts by mass or less, preferably 0.1 to 20 parts by mass, and more preferably about 1 to 15 parts by mass with respect to 100 parts by mass of the fabric.

(Outer cover layer)
The outer cover (protective) layer may contain a thermoplastic olefin polymer. In the present invention, since the thermoplastic olefin polymer forming the transport surface of the transport belt is contained, the stain resistance and non-adhesiveness (release property) of the transport belt can be improved, and the easily sticky transported object can be efficiently transported. ..

As the thermoplastic olefin polymer, the thermoplastic olefin polymer exemplified as the thermoplastic olefin polymer of the first adhesive layer can be used alone or in combination of two or more. Among the thermoplastic olefin-based polymers, a polymer of the same type (particularly the same) as the thermoplastic olefin-based polymer of the first adhesive layer is preferable from the viewpoint of improving the adhesion to the first adhesive layer. Therefore, when the thermoplastic olefin polymer of the first adhesive layer is a polyethylene resin, the thermoplastic olefin polymer of the outer peripheral cover layer is also preferably a polyethylene resin. Further, from the viewpoint of durability such as crack resistance, the thermoplastic olefin polymer is preferably a polyethylene resin such as LLDPE (particularly, a polyethylene resin having a low density).

The outer cover layer may also contain the conventional additives exemplified in the section of the first adhesive layer in addition to the thermoplastic olefin polymer. The ratio of the additive is 30 parts by mass or less, preferably 0.1 to 20 parts by mass, and more preferably 1 to 15 parts by mass with respect to 100 parts by mass of the thermoplastic olefin polymer.

The proportion of the thermoplastic olefin polymer in the outer peripheral cover layer may be 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and 100% by mass (only the polymer component). You may.

The average thickness of the outer peripheral cover layer can be selected from the range of about 0.05 to 1.5 mm (particularly 0.05 to 1.2 mm), for example, 0.05 to 1 mm, preferably 0.1 to 0.5 mm, more preferably. Is about 0.12 to 0.3 mm (particularly 0.13 to 0.2 mm). If the average thickness of the outer cover layer is too thin, the non-adhesiveness and stain resistance may decrease, and if it is too thick, cracks are likely to occur or the flexibility is reduced, so that the small diameter pulley can be used. It may be difficult to use.

(Second adhesive layer and second core body)
The second adhesive layer may contain a thermoplastic amorphous polymer. As the thermoplastic amorphous polymer of the second adhesive layer, the thermoplastic amorphous polymer exemplified as the thermoplastic amorphous polymer of the first adhesive layer can be used, and a preferred embodiment is also the thermoplasticity of the first adhesive layer. Similar to amorphous polymers.

The second adhesive layer may further contain the thermoplastic olefin polymer exemplified as the thermoplastic olefin polymer of the first adhesive layer in addition to the thermoplastic amorphous polymer. A preferred embodiment of the thermoplastic olefin polymer of the second adhesive layer is the same as that of the thermoplastic olefin polymer of the first adhesive layer. The ratio of the thermoplastic olefin polymer of the second adhesive layer may be 300 parts by mass or less with respect to 100 parts by mass of the thermoplastic amorphous polymer of the second adhesive layer, for example, 200 parts by mass or less (for example, 1). ~ 200 parts by mass), preferably 100 parts by mass or less, and more preferably 50 parts by mass or less.

The average thickness of the second adhesive layer is, for example, 0.05 to 1 mm, preferably 0.1 to 0.5 mm, and more preferably about 0.15 to 0.4 mm.

The second core body may contain a cloth. As the cloth of the second core body, the cloth exemplified as the cloth of the first core body can be used, and the preferred embodiment is the same as that of the cloth of the first core body. The fabric of the second core is usually the same as the fabric of the first core. The second core may also further contain the resin component, the curing agent and the additive exemplified in the section of the first core between the fibers inside the fabric. The preferred embodiments and proportions of the resin component, the curing agent and the additive are also the same as those of the first core body.

(Third adhesive layer and inner cover layer)
The third adhesive layer may contain a polymer alloy of a thermoplastic olefin polymer and a thermoplastic amorphous polymer. As the thermoplastic olefin polymer and the thermoplastic amorphous polymer of the third adhesive layer, the polymers exemplified as the thermoplastic olefin polymer and the thermoplastic amorphous polymer of the first adhesive layer can be used, and the preferred embodiments are also the same. Is. Further, the characteristics of the third adhesive layer are the same as those of the first adhesive layer, including preferable aspects. The third adhesive layer is usually the same as the first adhesive layer.

The inner peripheral cover layer may contain a thermoplastic olefin polymer. As the thermoplastic olefin polymer of the inner peripheral cover layer, similarly to the thermoplastic olefin polymer of the outer peripheral cover layer, the thermoplastic olefin polymer exemplified as the thermoplastic olefin polymer of the first adhesive layer may be used alone or twice. Can be used in combination with more than seeds. The inner peripheral cover layer is also the same as the outer peripheral cover layer, including the preferred embodiment, and is usually the same as the outer peripheral cover layer.

[Manufacturing method of conveyor belt]
The transport belt of the present invention can be manufactured by a conventional method such as a laminating method, and in the case of a belt having a three-layer structure, for example, a sheet-like precursor of a first adhesive layer and an outer peripheral cover layer is laminated on the outer peripheral surface side of the core body. It may be manufactured by the method described above. In the laminating method, the sheet-like precursor may be laminated on the core body in a molten state and adhered by solidification. The heating temperature for melting the sheet-like precursor can be selected depending on the type of polymer, but may be, for example, 100 ° C. or higher, preferably 100 to 200 ° C., more preferably 120 to 180 ° C. be. At the time of heating, pressurization may be performed, and the pressure is, for example, 0.1 MPa or more, preferably 0.1 to 0.6 MPa, and more preferably about 0.2 to 0.5 MPa. The heating time may be, for example, 10 seconds or more, for example, 30 seconds to 10 minutes, preferably about 1 to 8 minutes. Even if the transport belt has a multi-layer structure of five or more layers, each layer can be formed on the inner peripheral surface of the core body by the same laminating method.

As a method for producing the core body, a conventional method can be used, and examples thereof include a method of impregnating a liquid composition containing a resin component and a solvent with a cloth.

Examples of the solvent of the liquid composition include hydrocarbons (for example, alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as toluene and xylene), halogenated hydrocarbons (chloroform, dichloromethane and the like), and the like. Ethers (chain ethers such as diethyl ether, cyclic ethers such as dioxane and tetrahydrofuran), ketones (acetones, methyl ethyl ketones, etc.), esters (methyl acetate, ethyl acetate, etc.), amides (eg, formamide, N, N) -Includes dimethylformamides, etc.), nitriles (eg, acetonitrile, etc.), sulfoxides (eg, dimethylsulfoxide, etc.) and the like. These organic solvents can be used alone or as a mixed solvent. Among these solvents, hydrocarbons, ketones, cyclic ethers and the like are widely used. The concentration of the resin component in the liquid composition is, for example, 1 to 50% by mass, preferably 10 to 40% by mass, and more preferably about 20 to 30% by mass.

After the immersion, the fabric taken out from the liquid may be heat-dried at, for example, 80 ° C. or higher, preferably 80 to 200 ° C., and more preferably 100 to 150 ° C.

The form of the obtained transport belt is not particularly limited and may be a belt having no joint (seamless belt), but is usually an endless belt that joins both ends. FIG. 5 is a side view of the transport belt of the present invention prepared in an endless shape and mounted on a pulley. As shown in FIG. 5, the obtained transport belt 10 is used by being wound between the drive pulley 11 and the driven pulley 12 after being prepared into an endless belt by joining both ends. Specifically, a transported object such as food is placed on the transport belt 10 mounted on the pulley, and can be transported from the driven pulley 12 side to the drive pulley 11 side.

The method of joining both ends of the obtained transport belt is not particularly limited, but usually, in order to firmly fix the joint, both ends are formed in a non-linear shape such as a zigzag shape (lightning shape), and the joint is further formed. A method of covering with a reinforcing member is used.

FIG. 6 is a plan view of a joint portion of the transport belt of the present invention prepared in an endless shape. As shown in FIG. 6, first, the obtained transport belt is cut at both ends in the longitudinal direction in a zigzag shape (lightning shape), and the cut ends are abutted against each other. Next, as shown in FIG. 6, a reinforcing member 10a [for example, a sheet of the same material as the outer peripheral cover layer (for example, a polyethylene resin), a woven fabric, etc.] is laminated on the joint portion where both ends are joined. Then, using a hot plate press machine, the joint portion of the transport belt is joined by pressurizing the joint portion together with the reinforcing member.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[Details of raw materials used]
(Outer cover layer)
LLDPE: Sheet-like precursor formed of linear low-density polyethylene with a density of 0.9 g / cm ³ and melt mass flow rate (MFR) of 5.0 g / 10 min PP: Propylene homopolymer with a ^{density of 0.9 g / cm 3 (} Core body)
Plain woven fabric: The warp is a polyester spun yarn (total fineness 590 dtex yarn obtained by twisting two 20-count raw yarns, yarn density: 78 yarns / 5 cm), and the weft yarn is a polyester monofilament yarn (total fineness 660 dtex, yarn density: 68 pieces / 5 cm) Sail cloth Resin component: Polyester type polyurethane thermoplastic elastomer, hardness 85 degrees (JIS-A), melt viscosity 5000 Pa · s
Hardener: Polyisocyanate composition Solvent: Mixed solvent of methyl ethyl ketone, cyclohexane and tetrahydrofuran (methyl ethyl ketone / cyclohexane / tetrahydrofuran = 15/45/40 (mass ratio))
(Adhesive layer)
A sheet-like precursor formed by mixing the LLDPE and the polyether-type polyurethane thermoplastic elastomer in a predetermined ratio.

[MFR]
According to JIS K7210 (1999), the measurement was performed at a temperature of 190 ° C., a load of 21.18 N, and a die shape of φ2.095 × 8 mm.

[Melting viscosity]
According to JIS K7311 (1995), the measurement was performed at a temperature of 180 ° C., a load of 294 N, and a die shape of φ1 × 1 mm.

[Average thickness of outer cover layer and adhesive layer]
For the average thickness of the outer peripheral cover layer and the adhesive layer, the cross section of the transport belt was observed using a scanning electron microscope, and the average value of the thickness at any three points was calculated.

[Adhesive strength]
The transport belts obtained in Examples 1 to 3 and Comparative Example 1 were cut into test pieces having a width of 25 mm and a length of 150 mm. The force was measured. Specifically, regarding the three-layer structure transport belt obtained in the examples, as shown in FIG. 7, the interface A between the outer peripheral cover layer and the adhesive layer and the interface B between the adhesive layer and the core body. The adhesive strength was measured, and for the two-layer structure transport belt obtained in the comparative example, the adhesive strength at the interface C between the core body and the outer peripheral cover layer was measured as shown in FIG.

[Durability (running test)]
Both ends of the transport belts obtained in Examples 1 to 3 and Comparative Example 1 were formed in a zigzag shape (lightning shape). The obtained both ends are abutted against each other, and a sheet (width 100 mm, length about 50 mm) same as the sheet-like precursor for forming a cover layer so as to cover the joint is covered as a reinforcing layer, and then heat is applied. By joining by fusion, an endless transport belt having a width of 100 mm and a length of 1500 mm was produced, which was formed by a belt main body and a joint reinforced by a reinforcing layer.

The obtained endless transport belt was bridged over a 5-axis traveling tester whose schematic layout is shown in FIG. 9, and a traveling test was conducted under the conditions of a belt tension of 3 N / mm and a belt speed of 150 m / min. The pulley diameter was carried out in four stages of 40 mm, 30 mm, 20 mm and 10 mm. The running test was carried out until cracks were formed on the belt surface, and the running test was terminated after a maximum of 100 hours.

Example 1
The plain weave cloth is immersed in a liquid composition (solid content concentration: 25% by mass) containing a resin component and a curing agent for 30 seconds and taken out, and then heated and dried at 120 ° C. for 5 minutes to remove the solvent, and the core body is removed. Got Adhesive was attached to the surface of this core canvas. Next, on the core body, a sheet-like precursor of a polymer alloy (LLDPE: TPU = 30: 70 (mass ratio)) of LLDPE and a polyether polyurethane thermoplastic elastomer (TPU) and a sheet-like precursor of LLDPE. Was laminated in this order and heat-pressed at 150 ° C. and 0.3 MPa for 5 minutes using a press machine to melt the sheet-like precursor, which was then cooled and solidified to obtain a transport belt. The average thickness of the outer peripheral cover layer was 0.15 mm, and the average thickness of the adhesive layer was 0.2 mm.

Example 2
A transport belt was produced in the same manner as in Example 1 except that the mass ratio of LLDPE to the polyether polyurethane thermoplastic elastomer was LLDPE: TPU = 50: 50.

Example 3
A transport belt was produced in the same manner as in Example 1 except that the mass ratio of LLDPE to the polyether polyurethane thermoplastic elastomer was LLDPE: TPU = 70:30.

Example 4
A transport belt was produced in the same manner as in Example 3 except that PP was used instead of LLDPE as the material of the outer peripheral cover layer.

Example 5
A transport belt was produced in the same manner as in Example 3 except that the thickness of the sheet-like precursor of LLDPE was increased and the average thickness of the outer peripheral cover layer was 0.5 mm.

Example 6
A transport belt was produced in the same manner as in Example 3 except that the thickness of the sheet-like precursor of LLDPE was increased and the average thickness of the outer peripheral cover layer was 0.8 mm.

Example 7
A transport belt was produced in the same manner as in Example 3 except that the thickness of the sheet-like precursor of LLDPE was increased and the average thickness of the outer peripheral cover layer was 1.1 mm.

Example 8
A transport belt was produced in the same manner as in Example 3 except that the thickness of the sheet-like precursor of the polymer alloy of LLDPE and TPU was increased so that the average thickness of the adhesive layer was 0.5 mm.

Example 9
A transport belt was produced in the same manner as in Example 3 except that the thickness of the sheet-like precursor of the polymer alloy of LLDPE and TPU was increased to make the average thickness of the adhesive layer 0.8 mm.

Example 10
A transport belt was produced in the same manner as in Example 3 except that the thickness of the sheet-like precursor of the polymer alloy of LLDPE and TPU was increased to make the average thickness of the adhesive layer 1.1 mm.

Comparative Example 1
The transport belt is the same as in Example 1 except that the sheet-like precursor of LLDPE is laminated on the core sail cloth to which the adhesive is attached without using the polymer alloy of LLDPE and the polyether polyurethane thermoplastic elastomer. Was produced. The average thickness of the outer peripheral cover layer was 0.15 mm.

Comparative Example 2
A transport belt was produced in the same manner as in Comparative Example 1 except that the thickness of the sheet-like precursor of LLDPE was increased and the average thickness of the outer peripheral cover layer was 0.35 mm.

Table 1 shows the evaluation results of the transport belts obtained in Examples and Comparative Examples.

As is clear from the results in Table 1, in Comparative Examples 1 and 2 without an adhesive layer, the adhesive force between the core body and the outer peripheral cover layer is low, cracks occur in a relatively short time in the running test, and durability is achieved. The property (crack resistance) was low. In particular, Comparative Example 2 is an example in which the average thickness of the outer peripheral cover layer is 0.35 mm and the thickness of the entire belt is the same as that of Examples 1 to 3, but the durability is particularly low.

On the other hand, in Examples 1 to 3 having the adhesive layer of the polymer alloy of LLDPE and TPU between the core body and the outer peripheral cover layer, both the adhesive strength and the durability were high. Comparing Examples 1 to 3 in which the mixing ratio of LLDPE and TPU in the adhesive layer is changed, the adhesive strength of interface A is improved when the ratio of LLDPE is high, and the adhesive strength of interface B is improved when the ratio of TPU is high. You can see that it does. Looking at the durability, there was no big difference between Examples 1 to 3, but the durability of Example 3 was the highest.

Further, in Example 4 in which the material of the outer peripheral cover layer of Example 3 was changed from LLDPE to PP, the adhesive strength and durability of the interface A were slightly lowered, but the level was not a problem in practical use.

In Examples 5 to 7 in which the average thickness of the outer peripheral cover layer of Example 3 was changed, the durability tended to decrease as the average thickness of the outer peripheral cover layer increased. In particular, in Example 7 in which the average thickness of the outer peripheral cover layer was 1.1 mm, the degree of deterioration in durability was relatively large.

Further, in Examples 8 to 10 in which the average thickness of the adhesive layer of Example 3 was changed, the durability tended to decrease as the average thickness of the adhesive layer increased. In particular, in Example 10 in which the average thickness of the adhesive layer was 1.1 mm, the degree of deterioration in durability was relatively large.

The transport belt of the present invention can be used as a transport belt (conveyor belt) for various articles such as agricultural products, foods, and industrial products, and has excellent releasability. Therefore, highly sticky articles (for example, foods such as bread dough and confectionery dough) ) Is suitable as a conveyor belt.

1 ... 1st core body 2 ... 1st adhesive layer 3 ... Outer peripheral cover layer 4 ... 2nd adhesive layer 5 ... 2nd core body 6 ... 3rd adhesive layer 7 ... Inner peripheral cover layer

Claims (8)

A first core body containing a cloth, a first adhesive layer laminated on the outer peripheral surface side of the first core body, and an outer peripheral cover layer laminated on the first adhesive layer and forming a transport surface. A transport belt including, wherein the first adhesive layer contains a polymer alloy of a thermoplastic olefin polymer and a thermoplastic amorphous polymer, and the outer peripheral cover layer contains a thermoplastic olefin polymer. The thermoplastic amorphous polymer of the first adhesive layer is at least one selected from the group consisting of a thermoplastic styrene polymer, a thermoplastic vinyl chloride polymer, a thermoplastic (meth) acrylic polymer, and a thermoplastic urethane polymer. The transport belt according to claim 1. The transport belt according to claim 1 or 2, wherein the thermoplastic olefin polymer of the outer peripheral cover layer and the first adhesive layer contains a polyethylene resin. The transport belt according to any one of claims 1 to 3, wherein the first core body further contains a thermoplastic amorphous polymer. The transport belt according to any one of claims 1 to 4, wherein in the first adhesive layer, the mass ratio of the thermoplastic olefin polymer and the thermoplastic amorphous polymer is the former / the latter = 80/20 to 20/80. .. The transport belt according to any one of claims 1 to 5, wherein the outer peripheral cover layer has an average thickness of 0.05 to 1 mm, and the first adhesive layer has an average thickness of 0.05 to 1 mm. A second adhesive layer laminated on the inner peripheral surface side of the first core body and containing a thermoplastic amorphous polymer, and a second adhesive layer laminated on the second adhesive layer and containing a cloth are further added. The transport belt according to any one of claims 1 to 6, which includes. A third adhesive layer laminated on the inner peripheral surface side of the first core body and containing a polymer alloy of a thermoplastic olefin polymer and a thermoplastic amorphous polymer, and laminated on the third adhesive layer, and The transport belt according to any one of claims 1 to 6, further comprising an inner covering layer containing a thermoplastic olefin polymer.

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