JP7560065B2 - Synthetic canvas for industrial materials and its manufacturing method - Google Patents

Description

This invention relates to synthetic canvas for industrial use, which is used as the main material for tent warehouses (simple houses), rooftop tents (assembly tents with awnings that can be used for athletic meets, outdoor events, management headquarters, assemblies, reception desks, etc.), truck canopies, truck bed covers, open-air storage sheets, etc., and is lightweight and has excellent flexural durability (flutter resistance), especially at sub-zero temperatures and excellent heat resistance under the blazing sun.

For the main body material of tent warehouses, house tents, truck hoods, truck bed covers, open-air storage sheets, etc., synthetic canvas No. 4 to No. 6, made by impregnating and coating No. 4 to No. 6 spun cloth with a soft polyvinyl chloride resin composition, is used. These are mainly rated at 0.38 to 0.55 mm in thickness and 420 to 560 g/ ^m2 in weight, and the smaller the number, such as No. 6, No. 5, and No. 4, the heavier and more robust the synthetic canvas is. In the above applications, the larger the application scale (size), the more emphasis is placed on toughness and durability, and one rank higher canvas is sometimes used, such as No. 5 rather than No. 6, and No. 4 rather than No. 5, and sometimes No. 3 canvas (600 to 640 g/ ^m2 ) is used. This means an increase in mass for large-scale applications, and especially for applications such as house tents, truck bed covers, and open-air storage sheets, which are folded and stored when stored, the manual transportation, spreading, installation, and removal of the sheet are a huge burden of work. Therefore, for these applications, there is a strong demand for lighter, more durable synthetic canvas, for example, a synthetic canvas that has the weight of a No. 6 but the toughness and durability of a No. 5, or similarly, a synthetic canvas that has the weight of a No. 5 but the toughness and durability of a No. 4.

In response to this long-standing need, the applicant proposed an invention (Patent Document 1) for a canvas with excellent tear strength due to soft polyvinyl chloride resin processing, in which a plain weave fabric is used as the base fabric, the weave structure includes parallel yarns consisting of two staple spun yarns, the warp and weft include parallel yarns, and at least a portion where the warp and weft intertwine at the intersection point is made up of four staple spun yarns. In this invention, when comparing canvases using fabrics of the same size (mass) (Example 1/Comparative Example 1, Example 2/Comparative Example 2), a canvas with better tear strength was obtained, and the effects of the invention were described as being that a canvas that can exhibit the same tear strength as a conventional product can be obtained while using a lighter fabric than conventional products. Similarly, an invention (Patent Document 2) has been disclosed in which the warp and weft yarns constituting a fiber fabric contain one or more selected from spun yarns and multifilament yarns, the ranges of the spun yarns and multifilament yarns relative to the mass of the fiber fabric are individually specified, and the basis weight of the flexible laminate is set to 300 g/m ² or more and less than 450 g/m ² , as a flexible laminate that is excellent in strength, water resistance, flexibility, and durability and has improved lightness due to soft polyvinyl chloride resin processing. In this invention, it is described that the flexible laminate in the example has a basis weight of less than 450 g/m ² and is 10% to 25% lighter than the conventional flexible laminate in the comparative example, and furthermore, the tensile strength, tear strength, and elongation percentage are all equivalent to those of the conventional flexible laminate.

The canvas of Patent Document 1 and the flexible laminate of Patent Document 2 can improve physical properties such as tear strength and reduce weight by improving the weave of the fabric and changing the type of thread. However, the most effective way to reduce weight further is to reduce the thickness of the resin coating layer made of soft polyvinyl chloride resin, which has a high specific gravity. However, making the resin coating layer thinner directly adversely affects its flex resistance and abrasion resistance, making it weaker, and there is a high risk of water leakage (rain leakage) from cracks and abrasion scratches that occur, which directly leads to a decrease in quality. This risk can be avoided by improving the flex resistance and abrasion resistance of the resin coating layer even if the resin coating layer is made thinner. In other words, weight reduction is achieved by strengthening the soft polyvinyl chloride resin coating layer. Regarding the toughening of the soft vinyl chloride resin coating layer, the applicant previously disclosed in Patent Document 3 that the soft vinyl chloride resin layer contains a polyol compound, and a triisocyanate compound undergoes an addition reaction with the polyol compound to generate a crosslinked urethane component in the soft vinyl chloride resin layer, thereby improving the abrasion resistance, heat resistance, impact resistance, etc. of the soft vinyl chloride resin layer. The generation of this crosslinked urethane component improves the toughness of the soft vinyl chloride resin layer, but the more the amount of three-dimensional mesh-like crosslinked urethane by the triisocyanate compound (trifunctional monomer) increases, the harder the texture becomes in cold weather, and the soft vinyl chloride resin layer is vulnerable to cracking due to dynamic stress such as repeated bending, folding, and flapping, especially below freezing point. This is considered to be because the glass transition temperature difference between the soft vinyl chloride resin and the crosslinked urethane, and further the compatibility, deteriorate significantly below freezing point. Therefore, there has been a problem of improving the toughness of the soft vinyl chloride resin layer and improving it to one that is less likely to crack even when subjected to dynamic stress below freezing point. If this cracking problem at sub-zero temperatures can be solved, a synthetic canvas with better bending durability (flutter resistance) and foldability for storage can be obtained, which is expected to improve the service life of tent warehouses, roofed tents, truck canopies, truck bed covers, open-air storage sheets, etc. Furthermore, if the strength of the soft polyvinyl chloride resin layer is further improved, and the service life of conventional products can be ensured even if the amount of impregnation coating of the soft polyvinyl chloride resin layer is reduced by 10%, then it will be possible to reduce the weight without relying on the composition of the fiber fabric, as in Patent Document 2.

JP 2021-017668 A JP 2022-057803 A

The present invention aims to provide a synthetic canvas for industrial materials that is lightweight and has excellent flexural durability (flutter resistance), particularly at sub-zero temperatures and in the hot sun, and can be used as the main material for tent warehouses (simple houses), rooftop tents (assembly tents with awnings that can be used for athletic meets, outdoor events, management headquarters, assemblies, reception desks, etc.), truck canopies, truck bed covers, open-air storage sheets, etc.

As a result of extensive research and consideration of these points, the inventors discovered that in a synthetic canvas made by providing a soft polyvinyl chloride resin-impregnated coating layer on the entire surface of the fabric, by coexisting three-dimensional crosslinked rubber throughout the entire soft polyvinyl chloride resin-impregnated coating layer, it is possible to obtain a synthetic canvas for industrial use that has excellent flexural durability (flutter resistance), particularly at sub-freezing points, and excellent heat resistance under the hot sun, which led to the completion of the present invention.

The synthetic canvas for industrial materials of the present invention is a synthetic canvas made by providing a soft vinyl chloride resin impregnated coating layer on the entire surface of a fabric containing at least short fiber spun yarn as a weaving element, and three-dimensional crosslinked rubber is present throughout the entire area of the soft vinyl chloride resin impregnated coating layer , and the three-dimensional crosslinked rubber preferably contains one or more synthetic rubber structures selected from butadiene-based, isoprene-based, and farnesene-based . Within this soft vinyl chloride resin impregnated coating layer, a composite state is formed in which a network of three-dimensional crosslinked rubber is entangled with the vinyl chloride resin main chain, and by being in a compatible state, a synthetic canvas for industrial materials having excellent bending durability (flutter resistance), especially bending durability (flutter resistance) below freezing point and heat resistance under the hot sun can be obtained.

In the synthetic canvas for industrial materials of the present invention, the three-dimensional crosslinked rubber preferably contains one or more synthetic rubber structures selected from butadiene-based, isoprene-based, and farnesene-based. The three-dimensional crosslinked rubber forms a composite in which a network of the three-dimensional crosslinked rubber is entangled with the vinyl chloride resin main chain within the soft polyvinyl chloride resin-impregnated coating layer, and the resulting compatible state improves bending durability (flutter resistance), particularly bending durability (flutter resistance) below freezing point and folding resistance.

The synthetic canvas for industrial materials of the present invention is preferably an organic-inorganic hybrid rubber in which the three-dimensional crosslinked rubber contains silica particles and the silica particles are interposed as part of the three-dimensional crosslinking. The silanol groups (Si-OH groups) on the surface of the silica particles react and become part of the rubber component, thereby toughening the three-dimensional crosslinked rubber and improving its bending durability (flutter resistance) and abrasion resistance, and also improving the cold resistance and heat resistance (softening temperature) of the soft polyvinyl chloride resin-impregnated coating layer. This improved heat resistance is expressed not only in the improvement of the peel strength of the joint where the synthetic canvas for industrial materials is heat-sealed and lap-joined, but also in the peel resistance at surface temperatures of 40 to 60°C under the blazing sun.

In the synthetic canvas for industrial materials of the present invention, the silica particles are preferably surface-modified particles treated with a silane coupling agent. This surface modification is achieved by bonding a hydrolyzate of the silane coupling agent to the surface of the silica particles. In addition, the silica particles have functional groups, which can react with the terminal functional groups of the liquid synthetic rubber and become part of the three-dimensional crosslinking. This strengthens the three-dimensional crosslinked rubber, improving its bending durability (flutter resistance) and abrasion resistance, and also improving the cold resistance and heat resistance (softening temperature) of the soft polyvinyl chloride resin-impregnated coating layer. This improved heat resistance not only improves the peel strength of the joint where the synthetic canvas for industrial materials is heat-sealed and lap-joined, but also manifests itself as peel resistance at surface temperatures of 40 to 60°C under the blazing sun.

The synthetic canvas for industrial materials of the present invention preferably further comprises one or more selected from the group consisting of taslan bulky yarn, woolly bulky yarn, and core-spun sheath-core yarn. By using bulky long fiber yarns such as taslan bulky multifilament yarn, woolly bulky multifilament yarn, and core-spun sheath-core (long fiber core) yarn, the shortcomings of short fiber spun yarns, which have poor strength, are compensated for, and the bulky portion acts as an anchor for the soft polyvinyl chloride resin-impregnated coating layer, improving adhesion to the soft polyvinyl chloride resin-impregnated coating layer.

The manufacturing method of the synthetic canvas for industrial materials of the present invention, in which a soft polyvinyl chloride resin-impregnated coating layer is formed on the entire surface of a fabric, preferably includes the steps of: 1) preparing a soft polyvinyl chloride resin composition containing at least three types of polyvinyl chloride resin, a plasticizer, and liquid synthetic rubber (one or more selected from butadiene-based, isoprene-based, and farnesene-based rubbers); 2) applying the soft polyvinyl chloride resin composition to the fabric to form a soft polyvinyl chloride resin-impregnated coating layer; and 3) converting the liquid synthetic rubber into a crosslinked rubber to form a three-dimensional crosslinked rubber over the entire area of the soft polyvinyl chloride resin-impregnated coating layer. After coating, the liquid synthetic rubber molecules are present in the soft polyvinyl chloride resin-impregnated coating layer in a state where they are entangled with the polyvinyl chloride resin main chain. By crosslinking this liquid synthetic rubber, a composite state in which a three-dimensional crosslinked network is entangled with the polyvinyl chloride resin main chain is formed throughout the soft polyvinyl chloride resin-impregnated coating layer, resulting in a synthetic canvas for industrial use that has excellent bending durability (flutter resistance), especially bending durability (flutter resistance) below freezing points and heat resistance under the hot sun.

In the manufacturing method of the synthetic canvas for industrial materials of the present invention, it is preferable that the three-dimensional crosslinked rubber is formed by containing silica particles in the soft polyvinyl chloride resin composition, and the silica particles are interposed as part of the three-dimensional crosslinking, to form an organic-inorganic hybrid rubber. This makes the three-dimensional crosslinked rubber stronger, improving its bending durability (flutter resistance) and abrasion resistance, and also improving the heat resistance (softening temperature) of the soft polyvinyl chloride resin impregnated coating layer. This improved heat resistance is expressed not only in the improvement of the peel strength of the joint where the synthetic canvas for industrial materials is heat-sealed and lap-joined, but also in the peel resistance at a surface temperature of 40 to 60°C under the blazing sun, that is, the heat fastness of the joint. If the heat fastness of the joint is insufficient, the joint may peel and break when heat-sealed sewn products such as tent warehouses and truck hoods are subjected to external force.

The manufacturing method of synthetic canvas for industrial materials of the present invention preferably further includes a step of applying surface decorative embossing to the synthetic canvas. This surface decorative embossing can be mirror embossing (gloss), matte embossing (matte), pattern embossing (design), or letter engraving (recessed engraving of manufacturer name, product name, etc.), and the letter engraving of manufacturer name, product name, etc., in particular, provides an effect of distinguishing the product from similar products of other companies.

The present invention provides a synthetic canvas for industrial use that is lightweight and has excellent flexural durability (flutter resistance), particularly at sub-zero temperatures, and has excellent heat resistance under the hot sun. This allows for a wide range of uses, including as the main material for tent warehouses (simple houses), rooftop tents (assembly tents with awnings that are used for athletic meets, outdoor events, management headquarters, meetings, receptions, etc.), truck canopies, truck bed covers, and outdoor storage sheets.

The synthetic canvas for industrial materials of the present invention is a synthetic canvas made by providing a soft vinyl chloride resin-impregnated coating layer on the entire surface of a fabric that includes at least short fiber spun yarns as weaving and knitting elements, and in this embodiment, three-dimensional crosslinked rubber coexists throughout the entire area of the soft vinyl chloride resin-impregnated coating layer. Examples of fabrics that include short fiber spun yarns as weaving and knitting elements include A) spun fabrics woven only with short fiber spun yarns, and B) partially spun fabrics woven with a combination of short fiber spun yarns and yarns other than short fiber spun yarns, and examples of the yarns other than short fiber spun yarns include one or more types selected from taslan bulky yarns, woolly bulky yarns, and core spun core-sheath yarns. Taslan bulky yarn is a bulky long fiber yarn made by blowing compressed air onto a multifilament yarn to entangle the filaments in a loop shape, woolly bulky yarn is a bulky long fiber yarn made by twisting a multifilament yarn, heat setting it, and then untwisting it, and corespun core-sheath yarn is a pseudo-short fiber spun yarn with a core-sheath structure in which a multifilament long fiber yarn is used as a core and short fiber staples are entangled all around it in a mass ratio of 10:1 to 2:1. All three types of yarn have the strength of a multifilament long fiber yarn, but have hooks (fluff or loose bulk) equivalent to the fluff of short fiber spun yarn, which gives them the advantage of providing an anchoring effect to the soft polyvinyl chloride resin-impregnated coating layer. The amount of yarns other than the short fiber spun yarn is preferably 25 to 75% by mass, and more preferably 25 to 50% by mass, of the fabric.

In a fabric consisting of a warp thread group and a weft thread group, the combination of staple fiber spun yarns and yarns other than staple fiber spun yarns can be 1) combined with one or both of the warp thread group and the weft thread group (regular or random), or 2) combined with only staple fiber spun yarns in either the warp thread group or the weft thread group, and only yarns other than staple fiber spun yarns in the other. The same combination patterns can also be used in triaxial weave fabrics consisting of a warp thread group and a bias thread group, and in quadriaxial weave fabrics consisting of a warp thread group, a weft thread group, and a bias thread group. Examples of fabrics include plain weave, twill weave, satin weave, twill weave, basket weave, etc., with a void ratio of 0 to 10%, and plain weave fabrics with a void ratio of 0 to 10% are particularly preferred from the viewpoint of the balance of warp and weft physical properties of synthetic canvas for industrial materials. In these woven fabrics, by having, in whole or in part, a) two aligned short fiber spun yarns, b) two aligned yarns other than short fiber spun yarns, or c) one aligned short fiber spun yarn and one aligned yarn other than short fiber spun yarn, the tear strength of the fabric is improved, and the tear strength of the resulting synthetic canvas for industrial materials is also improved.

The fiber types of the staple spun yarn and yarns other than staple spun yarn (core spun yarn, multifilament yarn) include synthetic fibers (various polymers), natural fibers (cotton, kenaf), semi-synthetic fibers (rayon), and inorganic fibers (glass fiber, carbon fiber, etc.). In particular, synthetic fibers such as polypropylene fiber, polyethylene fiber, vinylon fiber, polyester fiber, nylon fiber, acrylic fiber, and polyurethane fiber are preferred in terms of the balance between versatility and physical properties, and polyester fiber, nylon fiber, and vinylon fiber are particularly preferred. In particular, in order to dramatically improve the tear resistance of the fabric, it is effective to use multifilament yarns of fully aromatic polyester fiber (polyarrelate), fully aromatic polyamide fiber (aramid), and aromatic heterocyclic polymer fiber (polybenzoxazole, polybenzimidazole, polybenzothiazole, etc.) in combination with the main yarn and arrange them in a ripstop pattern at specific intervals. In core spun yarns, the fiber type of the staple fiber used for the sheath is preferably the same as that of the core, but it may also be a combination of different types, for example a multifilament yarn of fully aromatic polyamide fiber (aramid) for the core and a polyester staple fiber for the sheath.

Examples of the count of the staple spun yarn include twisted yarns such as No. 10 single yarn (590 dtex), No. 14 single yarn (422 dtex), No. 14 two-ply yarn (844 dtex), No. 15 single yarn (394 dtex), No. 15 two-ply yarn (788 dtex), No. 20 single yarn (295 dtex), No. 20 two-ply yarn (590 dtex), No. 30 single yarn (197 dtex), and No. 30 two-ply yarn (394 dtex). Examples of twisted yarns include single yarns made by S (right) twisting or Z (left) twisting a single yarn or two single yarns, and two-ply yarns made by top twisting two twisted yarns made by undertwisting a single yarn or two single yarns. The number of twists of these twisted yarns is 200 to 2000 times/m, and the twist coefficient is preferably 3.0 to 4.5. A plain weave spun fabric is preferably obtained by weaving a warp yarn at a thread density of 40 to 80 threads per inch in parallel yarn units and a weft yarn at a thread density of 30 to 70 threads per inch. Particularly preferred is a spun plain weave fabric obtained by weaving a warp yarn of 20-count two-ply yarn and a weft yarn of 10-count single yarn at a weaving density of 52 to 60 warp yarns and 44 to 52 weft yarns per inch. This plain weave spun fabric may be partially spun fabric in which part of the warp and/or weft yarns is replaced with one or more types of yarns (fineness 278 dtex to 1666 dtex, number of filaments 50 to 500) selected from taslan bulky yarn, woolly bulky yarn, and core spun core-sheath yarn, with a replacement rate of 25 to 75% by mass, particularly 25 to 50% by mass, based on the mass of the fabric. The porosity of the above plain weave spun fabric and partially spun fabric is preferably 0 to 10%. If the porosity exceeds 10%, the dimensional stability of the resulting synthetic canvas will be poor, and the tear strength and penetration resistance against protrusions of the synthetic canvas may decrease.

The synthetic canvas for industrial materials of the present invention is preferably a fabric of 170 g/m ² to 410 g/m ² , and the size ranges are 2 (about 410 g/m ² ), 3 (about 340 g/m ² ), 4 (about 280 g/m ² ), 5 (about 250 g/m ² ), 6 (about 200 g/m ² ), and 7 (about 170 g/m ² ). In particular, when the soft polyvinyl chloride resin-impregnated coating layer of the synthetic canvas is damaged by scratches, wear, cracks, etc., rainwater may seep through the damaged area, causing water leakage problems. In order to prevent such water leakage, it is preferable to impregnate and attach a perfluoroalkyl group-containing copolymer resin to the entire fabric. The attached solid content of the perfluoroalkyl group-containing copolymer resin is 0.1 to 10 g/m ² per 1 m ² of the fabric, particularly 0.3 to 3 g/m ² . The perfluoroalkyl group-containing copolymer resin is a water-repellent copolymer made of an ethylenically unsaturated monomer having a perfluoroalkyl group having 8 or less carbon atoms, preferably 6 or less carbon atoms, or a perfluoroalkenyl group having 8 or less carbon atoms, preferably 6 or less carbon atoms. Specific examples of such a copolymer include emulsions of water-repellent copolymers obtained by polymerizing an acrylate and/or methacrylate having a perfluoroalkyl group with other monomers copolymerizable therewith, such as (meth)acrylic acid, (meth)acrylic acid esters, (meth)acrylamide, maleic acid or phthalic acid alkyl esters, vinyl chloride, vinylidene chloride, ethylene, styrene, etc. These water-repellent copolymers exhibit better water repellency by orienting and aligning the perfluoroalkyl groups during thermal curing at 120 to 180°C, thereby lowering the surface energy. Other water repellents that can be used include silicone-based water repellents such as methylchlorosilane, methylpolysiloxane resin, dimethylpolysiloxane, and methylhydrogenpolysiloxane, and paraffin-based water repellents such as n-paraffin wax having 20 to 48 carbon atoms and a melting point of 50 to 70° C.

The soft polyvinyl chloride resin-impregnated coating layer provided on the entire surface of the fabric is formed by coating a soft polyvinyl chloride resin composition and then gelling it through heat treatment, or by dipping the composition and then gelling it through heat treatment. The soft polyvinyl chloride resin composition is a liquid paste sol that contains at least three components: polyvinyl chloride resin, a plasticizer, and liquid synthetic rubber. Specifically, the soft polyvinyl chloride resin composition mainly contains a paste polyvinyl chloride resin (emulsion polymerization type) having a number average molecular weight of 1000 to 2000, 40 to 100 parts by mass of a plasticizer (such as an adipic acid ester compound, a phthalic acid ester compound, a cyclohexane dicarboxylate compound, a cyclohexene dicarboxylate compound, a phosphate compound, a chlorinated paraffin compound, or a polyester compound) per 100 parts by mass of the paste polyvinyl chloride resin, and 5 to 30 parts by mass of a liquid synthetic rubber (such as a butadiene rubber or an isoprene rubber, which is converted into a crosslinked rubber later) per 100 parts by mass of the paste polyvinyl chloride resin. Other compounding agents include stabilizers (barium-zinc complexes, calcium-zinc complexes, epoxidized soybean oil, etc.), flame retardants (antimony trioxide, antimony pentoxide, aluminum hydroxide, magnesium hydroxide, zinc borate, etc.), fillers (calcium carbonate, barium sulfate, silica, talc, etc.), light resistance stabilizers (benzophenone tautomers, benzotriazole tautomers, triazine tautomers, hindered amine compounds, etc.), adhesives (multifunctional isocyanate compounds, silane coupling agents, etc.), antifungal agents (imidazo Compound compositions containing any amount of the above compounds are preferred, and these compounds may contain any amount of additives such as fluorescent whitening agents, antistatic agents, surfactants, lubricants, antioxidants, chemical foaming agents, insect repellents, deodorants, and heat shielding agents, as needed.

The liquid synthetic rubber may be one or more selected from butadiene rubber, isoprene rubber, and farnesene rubber. The liquid synthetic rubber is compatible with the plasticizer contained in the soft vinyl chloride resin composition, and penetrates into the vinyl chloride resin fine particles together with the plasticizer to become a softener for the vinyl chloride resin. In this state, the soft vinyl chloride resin composition is heated and gelled to form a soft vinyl chloride resin impregnated coating layer. After coating, the soft vinyl chloride resin impregnated coating layer has liquid synthetic rubber molecules entangled with the vinyl chloride resin main chain. Next, the liquid synthetic rubber is crosslinked to form a composite state in which a three-dimensional crosslinked rubber network is entangled with the vinyl chloride resin main chain throughout the soft vinyl chloride resin impregnated coating layer. In particular, butadiene liquid rubber has either a -COOH group or a -OH group at the molecular end, which enables three-dimensional crosslinking. The molecular weight Mn is preferably 1000 to 5000, particularly 1300 to 3500, and the viscosity is preferably 50 to 1000 poise (25°C), particularly 200 to 500 poise (25°C). The butadiene liquid rubber contains 5 to 25% by mass of styrene and/or acrylonitrile as a block copolymerization component, and 10 to 50% by mass of isoprene or hydrogenated isoprene as a copolymerization component. The butadiene liquid rubber has a low viscosity and excellent rubber elasticity when rubberized if it has about 75 to 80% of 1,4-cis structure or 1,4-trans structure and about 20 to 25% of 1,2-vinyl structure. This production ratio is made possible by a radical polymerization method. The isoprene liquid rubber is preferably one having either a -COOH group or a -OH group at (both) molecular ends and a molecular weight Mn in the range of 3000 to 25000. The isoprene-based liquid rubber contains 5 to 25% by mass of styrene and/or acrylonitrile as a block copolymerization component, and 10 to 50% by mass of butadiene or hydrogenated isoprene as a copolymerization component. Examples of farnesene-based rubber include rubbers containing monomers such as α-farnesene ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodecatetraene) and β-farnesene (7,11-dimethyl-3-methylene-1,6,10-dodecatriene), as well as copolymer rubbers of farnesene and styrene and copolymer rubbers of farnesene and butadiene. The funnelsen-based liquid rubber preferably has either a -COOH group or a -OH group at (both) molecular ends and has a molecular weight Mn in the range of 3000 to 50000. The three-dimensional crosslinks of these liquid synthetic rubbers are formed by dehydration condensation of the -COOH and -OH groups at the (both) ends of the molecule, but can also be formed by addition reactions with crosslinking agents such as diamines, polyamines, diisocyanates, polyisocyanates, epoxy-amines, aziridines, and oxazolines, or condensation reactions with compounds such as diols, polyols, dicarboxylic acids, and polycarboxylic acids. Furthermore, organic-inorganic hybrid three-dimensional crosslinks containing silica can be used as part of the three-dimensional crosslinks.

For the three-dimensional crosslinked rubber, organic-inorganic hybrid rubber in which silica particles are interposed as part of the three-dimensional crosslinking is preferred. Silica is used in an amount of 1 to 25% by weight relative to the liquid synthetic rubber, and is made part of the three-dimensional crosslinking by forming chemical bonds between the functional groups on the silica surface and the -COOH and -OH groups at the molecular ends (both) of the liquid synthetic rubber. This reaction is formed by dehydration condensation between the -COOH and -OH groups at the molecular ends (both) of the liquid synthetic rubber and the silanol groups on the silica surface, but it is preferable to bond the functional groups of the liquid synthetic rubber and the silanol groups of the silica particles by addition reaction with crosslinking agents such as diamines, polyamines, diisocyanates, polyisocyanates, epoxy-amines, aziridines, and oxazolines, or by condensation reaction with compounds such as diols, polyols, dicarboxylic acids, and polycarboxylic acids. This three-dimensional crosslinked rubber is produced simultaneously with the gelling heat treatment of the soft polyvinyl chloride resin paste that forms the soft polyvinyl chloride resin-impregnated coating layer, forming a homogeneous three-dimensional crosslinked rubber throughout the soft polyvinyl chloride resin-impregnated coating layer. The soft polyvinyl chloride resin paste composition preferably contains a silane coupling agent to aid in the chemical bonding between the liquid synthetic rubber and the silica.

The silica is preferably synthetic amorphous silica having a BET specific surface area of 100 to 300 m ² /g or a secondary particle diameter of 1 to 40 μm. The synthetic amorphous silica may be either wet-process silica (precipitation method or gel method) or dry-process silica (fumed silica). The surface of the silica has silanol (Si-OH group), and the silanol group reacts with -COOH group, -OH group, etc. at (both) molecular ends of the liquid synthetic rubber, and the silica particles become part of the rubber component, thereby toughening the three-dimensional crosslinked rubber, improving bending durability (flutter resistance) and abrasion resistance, and also improving the cold resistance and heat resistance (softening temperature) of the soft polyvinyl chloride resin-impregnated coating layer. This improved heat resistance is expressed not only in the improvement of the peel strength of the joint where synthetic canvases for industrial materials are heat-sealed and lap-joined, but also in the peel resistance at a surface temperature of 40 to 60° C. under the blazing sun. Functional groups such as amino groups, vinyl groups, epoxy groups, methacryl groups, acrylic groups, chlorine groups, mercapto groups, isocyanurate groups, and isocyanate groups may be introduced to the silica surface. The silica particles are preferably surface-modified particles treated with a silane coupling agent. The silane coupling agent is an alkoxysilane compound having two or more different reactive groups in the molecule represented by the general formula: XR-Si(Y) ₃ , for example, X=amino group (aminosilane), vinyl group (vinylsilane), epoxy group (epoxysilane), methacryl group (methacrylsilane), acrylic group (acrylicsilane), chlorine group (chlorosilane), mercapto group (mercaptosilane), isocyanurate group (isocyanuratesilane), isocyanate group (isocyanatesilane), etc. (R=alkyl chain), Y=methoxy group, ethoxy group, etc. The surface modification of silica is a --Si--R--Si(Y) ₃ modification of the silanol groups of silica, but may also be an (--O) ₃ Si--RX modification of the siloxane bond moieties of silica.

The method for producing synthetic canvas for industrial materials of the present invention includes the steps of 1) preparing a soft vinyl chloride resin composition containing at least three components: vinyl chloride resin, plasticizer, and liquid synthetic rubber; 2) applying the soft vinyl chloride resin composition to a fabric to form a soft vinyl chloride resin-impregnated coating layer; and 3) converting the liquid synthetic rubber into a crosslinked rubber to form a three-dimensional crosslinked rubber over the entire area of the soft vinyl chloride resin-impregnated coating layer, and optionally applying a surface decorative embossing. The application of the soft vinyl chloride resin composition (paste sol) to the fabric and the formation of the soft vinyl chloride resin-impregnated coating layer can be carried out by dipping (immersion - impregnation - roll squeezing - heat treatment gelation of the paste sol) or coating (impregnation coating - heat treatment gelation of the paste sol) such as gravure coating, comma coating, roll coating, reverse roll coating, bar coating, and doctor knife coating. To convert liquid synthetic rubber into crosslinked rubber, a crosslinking agent such as diamine, triamine, tetramine, polyamine, diisocyanate (e.g., hexamethylene diisocyanate: HMDI), triisocyanate (e.g., isocyanurate by HMDI trimer), polyisocyanate, epoxy-amine, aziridine, oxazoline, etc., particularly a crosslinking agent having three or four functional groups, can be used to make a dense and complex three-dimensional crosslinked rubber. The conversion of liquid synthetic rubber into crosslinked rubber is carried out simultaneously with the gelation of the soft vinyl chloride resin composition, so that a homogeneous three-dimensional crosslinked rubber is formed throughout the soft vinyl chloride resin-impregnated coating layer. The reaction between the liquid synthetic rubber and the crosslinking agent is preferably an equimolar reaction, but excess liquid synthetic rubber may remain in the soft vinyl chloride resin-impregnated coating layer. The remaining liquid synthetic rubber is compatible with the plasticizer and acts to lower the glass transition temperature of the soft vinyl chloride resin-impregnated coating layer, i.e., as a cold resistance imparting agent. The remaining liquid synthetic rubber is preferably 1 to 10 parts by mass per 100 parts by mass of polyvinyl chloride resin.

The soft polyvinyl chloride resin-impregnated coating layer preferably has a weight per unit area of 200 to 400 g/ ^m2. The lower the weight per unit area, the lighter the weight will be, and the higher the weight per unit area, the stronger the material will be and the more durable it will be. Conventional synthetic canvas for industrial materials is made of No. 2 (about 410 g/m ² ), No. 3 (about 340 g/m ² ), No. 4 (about 280 g/m ² ), No. 5 (about 250 g/m ² ), No. 6 (about 200 g/m ² ) and No. 7 (about 170 g/m ² ) fabrics as a base fabric, with a soft polyvinyl chloride resin impregnated coating layer provided, and No. 2 canvas (about 750 g/m ² ), No. 3 canvas (about 640 g/m ² ), No. 4 canvas (about 560 g/m ² ), No. 5 canvas (about 530 g/m ² ), No. 6 canvas (about 470 g/m ² ), No. 7 canvas (about 430 g/m 2 ) and No. 8 canvas (about 850 g/m ^{2 ).} ) but with the synthetic canvas for industrial materials of the present invention, a soft polyvinyl chloride resin impregnated coating layer can be obtained that has at least a sufficient basis weight compared to conventional products, making it possible to reduce the weight by one rank, for example, to No. 4 canvas of approximately 530 g/ ^m2 , No. 5 canvas of approximately 470 g/ ^m2 , No. 6 canvas of approximately 430 g/ ^m2 , and No. 7 canvas of approximately 390 g/ ^m2 .

The synthetic canvas for industrial materials of the present invention may also be provided with an antifouling layer, which may be, for example, a transparent layer made of acrylic resin, fluorine-based copolymer resin, acrylic-silicone copolymer resin, acrylic-fluorine copolymer resin, acrylic-urethane copolymer resin, a blend of acrylic resin and fluorine-based copolymer resin, or a mixture of these resins with silica particles, colloidal silica, organosilicate, silane coupling agent, ultraviolet absorber (benzophenone tautomer, benzotriazole tautomer, triazine tautomer, etc.). These antifouling layers are formed by applying and drying these paints using gravure coating, or by laminating a fluorine-containing resin film or a multilayer film such as a fluorine-containing resin/acrylic resin layer with an adhesive or by thermal melting. In addition, a photocatalytic layer containing a photocatalytic inorganic material (for example, photocatalytic titanium oxide, photocatalytic tungsten oxide, etc.) may also be provided on these antifouling layers.

The manufacturing process of the synthetic canvas for industrial materials of the present invention may include a step of applying surface decorative embossing. Surface decorative embossing can be performed by known embossing methods, such as imparting gloss with a mirror roll, imparting matte finish with a matte finish roll, or imparting a design with a pattern roll. In particular, it is preferable to apply an identification mark of the manufacturer's name (e.g., "HIRAOKA"), logo mark, or product name (e.g., "ULTRA MAX") at specific intervals (e.g., every 100 cm) to the end or specific parts of the synthetic canvas for industrial materials. Such identification markings include a design in which the entire synthetic canvas is matte embossed and only the identification marking part is mirror embossed, or a design in which the entire synthetic canvas is mirror embossed and only the identification marking part is matte embossed, or an embossing with the identification marking part as a recess, and these markings make it easy to distinguish the product from similar products of other companies. The embossing is done by pressing an embossing roll set at 100-180°C against a pair of rubber rolls, and the embossing is fixed by cooling after embossing (air-cooled and water-cooled rolls).

The present invention will now be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the scope of these examples.
The test methods used in the examples and comparative examples of the present invention are as follows.
(1) Scott type reciprocating bending abrasion test (JIS L1096 8.19.2 B method)
Test pieces measuring 25 mm wide x 120 mm long were taken from the synthetic canvas and left to stand in a -10°C environment for 24 hours. They were then attached to a Scott-type testing machine and subjected to 500 and 1,000 reciprocating flexions under a load of 1 kgf in a constant temperature room at -10°C. The surface condition after the test was observed and the dynamic cold resistance was evaluated as follows.
1: No abnormality is observed 2: Minor cracks are observed in the soft polyvinyl chloride resin-impregnated coating layer 3: Partial peeling or falling off, or cracks are observed in the soft polyvinyl chloride resin-impregnated coating layer (2) Dematcha repeated bending fatigue durability test (JIS K6301 compliant)
A sample of 50 mm width x 150 mm length was taken from the synthetic canvas and left to stand in a -0°C environment for 24 hours. After that, a folded test piece of 25 mm width x 150 mm length was made by folding it in half from the center 25 mm of the width, and then attached to a YSS Dematcha Flexing Tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.). A pseudo test of repeatedly folding and unfolding the test piece was performed 500 times and 1000 times in a constant temperature room at -10°C. The surface condition of the test piece was observed and the dynamic cold resistance was evaluated as follows.
1: No abnormality is observed. 2: Minor cracks are observed in the soft polyvinyl chloride resin-impregnated coating layer. 3: Partial peeling or falling off, or cracks are observed in the soft polyvinyl chloride resin-impregnated coating layer. (3) Heat resistance creep test of the joint (heat resistance test)
The ends of two synthetic canvases in the weft direction were overlapped in a straight line in parallel with a width of 8 cm, and a high-frequency welder fusion machine (YTO-8A type, manufactured by Yamamoto Vinita Co., Ltd.: high-frequency output 8 kW) equipped with a weld bar (flat blade) of 4 cm width x 30 cm length was used to melt the soft vinyl chloride resin impregnated coating layer with an anode current of 1.0 A to obtain a synthetic canvas joint. A test piece of 3 cm width x 30 cm length (warp direction) including a width of 8 cm in the warp direction by overlapping the fusion joint parts from this joint was taken as a creep resistance test piece, and the heat creep resistance in the warp direction was evaluated using a creep tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.: 100LDR type) under conditions of 25 ° C x 24 hours and load conditions of 50 kgf, 60 kgf, and 70 kgf, and a test piece in the weft direction was similarly prepared to evaluate the heat creep resistance in the weft direction.
Evaluation criteria
1: After 24 hours, no abnormalities in the joint (Excellent)
2: The joint broke and the test piece broke apart within 12 to 24 hours (good)
3: The joint broke and the test piece broke apart within 1 to 12 hours (poor)
4: The joint broke and the test piece broke apart within 1 hour (failure)

Example 1
<Fabric (1)>
A No. 5 fabric was used, which was plain woven with a warp density of 54 threads/inch and a weft density of 46 threads/inch using 20-count two-ply polyester staple spun yarn (S twist 300 T/m) as the warp yarn and 10-count single-ply polyester staple spun yarn (S twist 400 T/m) as the weft yarn, and had a void ratio of 0 in appearance in terms of fluff and a mass of 240 g/ ^m2 .
The fabric was subjected to a water-repellent treatment (immersion, heat treatment) using an acrylate/vinyl chloride resin copolymer emulsion (solid content 5% by mass) having a perfluoroalkyl group having 6 or less carbon atoms to prevent rainwater penetration (water absorption) in the event that an abnormality occurs in the soft vinyl chloride resin-impregnated coating layer. This was designated fabric (1).
<Soft polyvinyl chloride resin impregnated coating layer>
A processing liquid was prepared that mainly contained a vinyl chloride resin composition paste (containing at least three kinds of vinyl chloride resin, plasticizer, and liquid synthetic rubber) for forming a soft vinyl chloride resin impregnated coating layer of the following <Composition 1>. Next, the fabric (1) was dipped (immersed) in a liquid bath filled with this processing liquid, and the processing liquid of <Composition 1> was impregnated into the fabric (1) at normal pressure, and then the fabric (1) was pulled out of the liquid bath and squeezed with a rubber mangle roll at the same time to remove excess processing liquid, forming a soft vinyl chloride resin impregnated coating layer. Next, a gelation heat treatment was performed in a hot air oven at 180°C for 3 minutes to form a soft vinyl chloride resin impregnated coating layer of 290g/ ^m2 on the entire surface of the fabric (1), and a No. 5 canvas (1) with a mass of 530g/ ^m2 was obtained. This gelation heat treatment is a process in which the vinyl chloride resin composition paste is converted into soft vinyl chloride resin and at the same time the liquid synthetic rubber is crosslinked and converted into a crosslinked rubber, thereby forming a hybrid in which a three-dimensional crosslinked network is entangled with the vinyl chloride resin main chain throughout the entire area of the resulting soft vinyl chloride resin-impregnated coating layer.
<Formulation 1> Processing fluid for forming soft polyvinyl chloride resin impregnated coating layer Paste polyvinyl chloride resin (polymerization degree 1700) 100 parts by weight Diisononyl phthalate (DINP plasticizer) 60 parts by weight Butadiene-based liquid rubber * 10 parts by weight Isocyanurate (HMDI * trimer: NCO crosslinking agent) 2 parts by weight Chlorinated paraffin (flame retardant and plasticizer) 5 parts by weight Epoxidized soybean oil (stabilizer and plasticizer) 4 parts by weight Antimony trioxide (flame retardant) 20 parts by weight Zinc stearate (stabilizer) 2 parts by weight UV absorber (triazine tautomer) 0.5 parts by weight Titanium oxide (white pigment) 1 part by weight Phthalocyanine green (green pigment) 3 parts by weight Carbon black (black pigment) 0.5 parts by weight Trichloroethylene (dilution solvent) 20 parts by weight *Butadiene-based liquid rubber: Contains 15% by mass of styrene as a block copolymer component.
It has an average molecular weight of 3000 and has -COOH groups at both ends of the molecule. *HMDI: Hexamethylene diisocyanate. HMDI trimer (isocyanurate) has three isocyanate groups.

Example 2
A No. 5 canvas (2) having a mass of 530 g/ ^m2 was obtained in the same manner as in Example 1, except that the processing liquid of <Blend 1> in Example 1 was changed to the processing liquid of <Blend 2>.
The processing fluid of <Blend 2> is obtained by replacing 10 parts by mass of the butadiene-based liquid rubber of <Blend 1> with 10 parts by mass of isoprene-based liquid rubber. The isoprene-based liquid rubber contains 10% by mass of acrylonitrile as a block copolymer component, has -COOH groups at both molecular terminals, and has an average molecular weight of 2,500.

Example 3
A No. 5 canvas (3) having a mass of 530 g/ ^m2 was obtained in the same manner as in Example 1, except that the processing solution of <Blend 1> in Example 1 was changed to the processing solution of <Blend 3>.
The processing fluid of <Blend 3> is obtained by replacing 10 parts by mass of the butadiene-based liquid rubber of <Blend 1> with 10 parts by mass of β-funnelsen-based liquid rubber. The β-funnelsen-based liquid rubber contains 10% by mass of butadiene as a block copolymer component, has -COOH groups at both molecular terminals, and has an average molecular weight of 5,000.

Example 4
A No. 5 canvas (4) having a mass of 530 g/ ^m2 was obtained in the same manner as in Example 1, except that the processing solution of <Blend 1> in Example 1 was changed to the processing solution of <Blend 4>.
The processing liquid of <Blend 4> is the processing liquid of <Blend 1> to which 2 parts by mass of surface-modified silica particles have been added.
The surface-modified silica particles are prepared by stirring dry silica (gel method: average particle size 2 μm, BET specific surface area 300 ^m2 /g) in a 5 mass% aqueous solution of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (silane coupling agent) at 24°C for 3 hours, then isolating and drying the resulting mixture contains a mixture of -Si-R-Si( _OCH3 ) ₃ modifications bonded to the silanol groups of the silica and (-O) _3Si -R- _NH2 modifications bonded to the siloxane moieties.

Example 5
A No. 5 canvas (5) having a mass of 530 g/ ^m2 was obtained in the same manner as in Example 2, except that the processing solution of <Blend 2> in Example 2 was changed to the processing solution of <Blend 4>.

Example 6
A No. 5 canvas (6) having a mass of 530 g/ ^m2 was obtained in the same manner as in Example 3, except that the processing solution of <Blend 3> in Example 3 was changed to the processing solution of <Blend 4>.

Example 7
The same procedure as in Example 4 was repeated except that the processing solution of <Blend 4> in Example 4 was changed to the processing solution of <Blend 5>, and a No. 5 canvas (7) having a mass of 530 g/ ^m2 was obtained.
The processing fluid of <Blend 5> is the processing fluid of <Blend 4> to which 2 parts by mass of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (a silane coupling agent) has been added.

Example 8
A No. 5 canvas (8) having a mass of 530 g/ ^m2 was obtained in the same manner as in Example 5, except that the processing solution of <Blend 4> in Example 5 was changed to the processing solution of <Blend 5>.

Example 9
The same procedure was followed as in Example 6, except that the processing solution of <Blend 4> in Example 6 was changed to the processing solution of <Blend 5>, to obtain a No. 5 canvas (9) having a mass of 530 g/ ^m2 .

Example 10
A canvas (10) having a mass of 470 g/ ^m2 was obtained in the same manner as in Example 1, except that the basis weight of the soft polyvinyl chloride resin impregnated coating layer provided in Example ¹ was reduced from 290 g/ ^m2 to 230 g/m2.

Example 11
A canvas (11) having a mass of 500 g/ ^m2 was obtained in the same manner as in Example 1, except that the fabric (1) used in Example 1 was changed to the fabric (2).
<Fabric (2)>
The warp yarns were made of 20-count two-ply polyester staple spun yarn (S twist 300 T/m) and 1000 denier (1111 dtex) Taslan bulky filament yarn made of polyester fiber (192 filaments) with the filaments loosely entangled with each other and S twisted 10 T/m, and the warp yarns were made of 10-count single-ply polyester staple spun yarn (S twist 400 T/m). The fabric was made of 1000 denier (1111 dtex) Taslan bulky long fiber yarns, which were loosely entangled with each other and had an S twist of 10 T/m, and were arranged alternately as weft yarns, with a warp thread pick density of 40 threads/inch and a weft thread pick density of 34 threads/inch, and had a void ratio of 0 in appearance in terms of fluff and a mass of 215 g/ ^m2 . The fabric was subjected to a water-repellent treatment (immersion, heat treatment) using an acrylate/vinyl chloride resin copolymer emulsion (solid content 5% by mass) having a perfluoroalkyl group with a carbon number of 6 or less to prevent rainwater penetration (water absorption prevention) in the event of an abnormality occurring in the soft vinyl chloride resin impregnated coating layer. This was designated fabric (2).

Example 12
A canvas (12) having a mass of 515 g/ ^m2 was obtained in the same manner as in Example 1, except that the fabric (1) used in Example 1 was changed to the fabric (3).
<Fabric (3)>
The warp yarns were made of a 20-count two-ply polyester staple spun yarn (S twist 300 T/m) and a core-sheath yarn having a 500 denier (555 dtex) polyester multifilament long fiber core covered all around with 1.4 denier (1.56 dtex) short fiber polyester staple with a length of 100 mm in a core/sheath ratio of 65/35 by weight, arranged alternately. The fabric used was a plain weave fabric with a warp thread pick density of 46 threads/inch and a weft thread pick density of 38 threads/inch, and a void ratio of 0 in appearance in terms of fluff, and a mass of 225 g/ ^m2 . The fabric was treated for water repellency (immersion, heat treatment) with an acrylate/vinyl chloride resin copolymer emulsion (solid content 5% by mass) having a perfluoroalkyl group with 6 or less carbon atoms to prevent rainwater penetration (water absorption prevention) in the event of an abnormality occurring in the soft vinyl chloride resin impregnated coating layer. This fabric was designated fabric (3).

[Example 13]
The surface of the synthetic canvas (1) of Resin Example 1 was coated with the fluororesin paint of the following Blend 6 using a 100 mesh gravure roll, and then heated and dried in a hot air oven at 120°C for 2 minutes to harden the fluororesin paint of Blend 6 and form an antifouling coating layer (4 g/ ^m2 ), thereby obtaining No. 5 canvas (13) with a mass of 534 g/ ^m2 .
<Formulation 6> Fluorine-based resin paint (for forming anti-fouling layer)
Hydroxyl-containing fluoroolefin vinyl ether copolymer (fluorine-based resin)
100 parts by weight Isocyanurate trimer of hexamethylene diisocyanate (isocyanate)
10 parts by weight Colloidal silica (antistatic) 8 parts by weight Triazine tautomer (ultraviolet absorbing agent) 5 parts by weight Curing catalyst: dibutyltin dilaurate (about 10 ppm relative to fluororesin)
Toluene/butyl acetate (diluent with a mass ratio of 1:1) 400 parts by mass

[Example 14]
The surface of the synthetic canvas (13) of Example 13 was stamped with an identification mark of "HIRAOKA" using an embossing roll at 180°C. The marking (convex) on the embossing roll side was in Gothic font, character size 15mm x 15mm, character width 3.5mm, convex part height 0.2mm, and the surface other than the stamped part was mirror-like. The identification mark of "HIRAOKA" on the surface of the synthetic canvas (13) was in Gothic font, character size 15mm x 15mm, character width 3.5mm, concave depth 0.12mm, and the surface other than the stamped part was mirror-like.

[Example 15]
The surface of the synthetic canvas (1) of Example 1 was stamped with an identification mark of "HIRAOKA" using an embossing roll at 180°C. The mark on the embossing roll side was in Gothic font (matte finish), with a character size of 15 mm x 15 mm, character width of 3.5 mm, and the surface other than the stamped area was mirror-finished. The identification mark of "HIRAOKA" on the surface of the synthetic canvas (1) was in Gothic font, with a character size of 15 mm x 15 mm, character width of 3.5 mm, and the surface other than the stamped area was mirror-finished.

[Example 16]
The surface of the synthetic canvas (1) of Example 1 was stamped with an identification mark of "HIRAOKA" using an embossing roll at 180°C. The mark on the embossing roll side was in Gothic font (mirror surface), with a character size of 15 mm x 15 mm, character width of 3.5 mm, and the surface other than the stamped area was matte. The identification mark of "HIRAOKA" on the surface of the synthetic canvas (1) was a mirror surface stamp with a Gothic font, character size of 15 mm x 15 mm, character width of 3.5 mm, and the surface other than the stamped area was matte.

In the synthetic canvases (1) to (12) of Examples 1 to 12, three-dimensional crosslinking of synthetic rubber is formed in the soft vinyl chloride resin impregnated coating layer, and the formation is performed by applying a soft vinyl chloride resin composition containing liquid synthetic rubber to the fabric, and then converting the liquid synthetic rubber into a crosslinked rubber to form a three-dimensional crosslinked rubber in the entire area of the soft vinyl chloride resin impregnated coating layer. In the applied soft vinyl chloride resin impregnated coating layer, liquid synthetic rubber molecules are present in a state entangled with the vinyl chloride resin main chain, and by crosslinking this liquid synthetic rubber, a hybrid in a state in which a three-dimensional crosslinked network is entangled with the vinyl chloride resin main chain can be formed in the entire area of the soft vinyl chloride resin impregnated coating layer, so that a synthetic canvas for industrial materials can be obtained that has excellent bending durability (flutter resistance), and is particularly excellent in bending durability below freezing (Scott bending abrasion test/De Mattia bending fatigue test) and heat resistance under the hot sun (bonding heat creep test). In particular, in the synthetic canvases (4) to (9) of Examples 4 to 9, the liquid synthetic rubber bonds (through a crosslinking agent) with the silanol groups (Si-OH groups) on the surface of the silica particles, and the three-dimensional crosslinked structure contains silica (treated with a silane coupling agent) as a relay point, which strengthens the three-dimensional crosslinked rubber and further improves the flexural durability (De Mattia flexural fatigue test) and abrasion resistance (Scott flexural abrasion test), as well as the cold resistance and heat resistance (bonding heat creep test) of the soft polyvinyl chloride resin impregnated coating layer. In particular, in order for the liquid synthetic rubber to bond with the silanol groups on the surface of the silica particles and to have silica interposed as a relay point in the three-dimensional crosslinked structure, the silane coupling agent is involved (Examples 7 to 9), which has the effect of assisting the formation of the three-dimensional crosslinked rubber. In addition, in Example 10, by reducing the basis weight of the soft polyvinyl chloride resin impregnated coating layer of Example 1, the flexural durability (De Mattia flexural fatigue test), abrasion resistance (Scott flexural abrasion test), and heat resistance (heat creep test for joints) were somewhat inferior, but it was possible to achieve a weight reduction (470 g/ ^m2 ) comparable to that of No. 6 canvas while satisfying the specifications of No. 5 canvas. It is superior in flexural durability (De Mattia flexural fatigue test), abrasion resistance (Scott flexural abrasion test), and heat resistance (heat creep test for joints) compared to the synthetic canvas of Comparative Example 1, which is the conventional No. 5 canvas (mass 530 g/ ^m2 ), and is approximately 60 g/ ^m2 lighter, which is desired in the industry. Furthermore, the fabric (1) of Example 10 is for use as No. 5 canvas, and since all of the yarns constituting the fabric are staple spun yarns, it has the disadvantage of being inferior to the tear strength of synthetic canvas (JIS L1096 trapezoid method). However, the combination of staple spun yarns and bulky Taslan yarns (long fibers) as in the fabric (2) of Example 11, and the combination of staple spun yarns and core spun sheath yarns (with long fibers as the core) as in the fabric (3) of Example 12, both contain long fibers, which improves and enhances the tear strength in both the warp and weft directions.Furthermore, it is possible to obtain a synthetic canvas for industrial use that has excellent flexural durability below freezing points (Scott flexural abrasion test/De Mattia flexural fatigue test) and heat resistance under the hot sun (heat resistant creep test for joints). Therefore, by replacing the fabric (1) in Example 10 with the fabric (2) or (3), a synthetic canvas for industrial use can be obtained that not only has the above-mentioned bending durability and heat resistance, but also has lightweight and excellent tear strength, thereby addressing the long-standing challenge of being "lightweight and high performance."

[Comparative Example 1]
Example 1 was repeated except that the processing solution of <Blend 1> in Example 1 was changed to the processing solution of <Blend 6>, and a No. 5 canvas (conventional product: 13) with a mass of 530 g/ ^m2 was obtained in the same manner as in Example 1.
The processing fluid of <Blend 6> is a conventional blend obtained by omitting 10 parts by mass of the butadiene-based liquid rubber (having --COOH groups at both molecular terminals and an average molecular weight of 3,000).
The conventional products in the comparative examples were inferior in flexural durability below freezing (Scott flexural wear test, De Mattia flexural fatigue test) and in heat resistance under the blazing sun (joint heat creep test), and a solution to this problem was desired. (Recent state of the art)

[Comparative Example 2]
A No. 5 canvas (14) having a mass of 530 g/ ^m2 was obtained in the same manner as in Example 1, except that the processing solution of <Blend 1> in Example 1 was changed to the processing solution of <Blend 7>.
The processing fluid of <Blend 7> is obtained by replacing 10 parts by mass of the butadiene-based liquid rubber (having -COOH groups at both molecular terminals and an average molecular weight of 3000) of <Blend 1> with 10 parts by mass of a butadiene-based liquid rubber having an average molecular weight of 3000 and no functional groups at both molecular terminals.
The butadiene-based liquid rubber, which has no functional groups, remains in a liquid state within the soft polyvinyl chloride resin-impregnated coating layer and exerts the effect of lowering the glass transition temperature of the polyvinyl chloride resin, resulting in superior bending durability (Scott flexure abrasion test/De Mattia flexure fatigue test) at temperatures below freezing points compared to the synthetic canvas of Comparative Example 1 (conventional product) (similar to the synthetic canvas (1) of Example 1). However, conversely, the presence of the butadiene-based liquid rubber had a negative effect on heat resistance (heat creep test for joints), making it inferior to the synthetic canvas of Comparative Example 1 (conventional product).

[Comparative Example 3]
A No. 5 canvas (15) having a mass of 530 g/ ^m2 was obtained in the same manner as in Example 1, except that the processing solution of <Blend 1> in Example 1 was changed to the processing solution of <Blend 8>.
The processing fluid of <Blend 8> is obtained by replacing 10 parts by mass of the butadiene liquid rubber (having -COOH groups at both ends of the molecule and having an average molecular weight of 3000) of <Blend 1> with 10 parts by mass of butadiene rubber powder (registered trademark "Kane Ace" M-711: Kaneka Corporation).
The butadiene rubber powder (non-crosslinked) was incompatible and dispersed in the soft polyvinyl chloride resin impregnated coating layer, and due to the cold resistance of the butadiene rubber itself, it was slightly better than the synthetic canvas of Comparative Example 1 (conventional product) in bending durability (Scott bending abrasion test, De Mattia bending fatigue test) at freezing points (not as good as the synthetic canvas (1) of Example 1), but countless cracks were generated due to the influence of the incompatible dispersion. Also, with regard to heat resistance (heat creep test of joints), no particular improvement was observed compared to the synthetic canvas of Comparative Example 1 (conventional product).

As is clear from the above examples and comparative examples, the present invention provides a synthetic canvas for industrial materials that is lightweight and has excellent bending durability (flutter resistance), especially at sub-freezing points and in the hot sun, allowing it to be widely used as the main material for tent warehouses (simple houses), rooftop tents (assembly tents with awnings used for athletic meets, outdoor events, management headquarters, meetings, receptions, etc.), truck canopies, truck bed covers, and open-air storage sheets. In particular, by applying an identifying mark such as the manufacturer's name, logo, or product name to the edge or specific parts of the synthetic canvas for industrial materials by surface decorative embossing, it becomes easy to distinguish it from similar products made by other companies.

Claims (7)

A synthetic canvas for industrial materials, comprising a base fabric containing at least short fiber spun yarns as weaving and knitting elements, and a soft polyvinyl chloride resin-impregnated coating layer provided on the entire surface of the base fabric, wherein three-dimensional crosslinked rubber coexists throughout the entire soft polyvinyl chloride resin-impregnated coating layer , and the three-dimensional crosslinked rubber contains one or more synthetic rubber structures selected from butadiene-based, isoprene-based, and farnesene-based synthetic rubbers . The synthetic canvas for industrial use according to claim 1 , wherein the three-dimensional cross-linked rubber is an organic-inorganic hybrid rubber containing silica particles and in which the silica particles are interposed as part of the three-dimensional cross-linking. The synthetic canvas for industrial use according to claim 2 , wherein the silica particles are surface-modified particles treated with a silane coupling agent. The synthetic canvas for industrial materials according to claim 1, wherein the fabric further contains one or more selected from the group consisting of taslan bulky yarn, woolly bulky yarn, and core-spun core-sheath yarn. A method for manufacturing synthetic canvas for industrial use, comprising the steps of: 1) preparing a soft vinyl chloride resin composition containing at least three components: vinyl chloride resin, a plasticizer, and liquid synthetic rubber (one or more selected from butadiene-based, isoprene-based, and farnesene-based); 2) applying the soft vinyl chloride resin composition to the fabric to form a soft vinyl chloride resin-impregnated coating layer; and 3) converting the liquid synthetic rubber into a crosslinked rubber to form a three-dimensional crosslinked rubber over the entire area of the soft vinyl chloride resin-impregnated coating layer. A method for producing a synthetic canvas for industrial materials as described in claim 5, wherein the three-dimensional crosslinked rubber is formed by containing silica particles in the soft polyvinyl chloride resin composition, and the silica particles are interposed as part of the three-dimensional crosslinking to produce an organic-inorganic hybrid rubber. The method for manufacturing a synthetic canvas for industrial materials according to claim 5 or 6 , further comprising a step of subjecting the synthetic canvas to a surface decorative embossing process.