FABRIC AND METHOD FOR MANUFACTURING THE SAME
Provided is a fabric that has excellent stain resistance and excellent flame retardancy and that is less likely to generate water spots and is less likely to cause pieces thereof to attach to each other, and a method of manufacturing the fabric. The fabric according to the present invention is a polyester fabric impregnated with a fluorinated water-and-oil repellent agent and includes a coating layer on one surface thereof, the coating layer containing a fluorinated water-and-oil repellent agent, an organic phosphorus flame retardant having a solubility in water at 20° C. of 4% or less, and an acrylic resin having a glass-transition temperature of −43° C. to −20° C.
The present invention relates to a functional fabric and a method of manufacturing the fabric. More specifically, the present invention relates to a fabric that has stain resistance and flame retardancy and that is less likely to generate water spots and cause pieces thereof to attach to each other, and a method of manufacturing the fabric.
Description of the Related ArtA fabric used for interior of, for example, cars, ships, and airplanes (for example, a fabric used for a seat of vehicles such as a car and for trim members such as a door lining) is required to have flame retardancy as well as high stain resistance because it is difficult to wash or clean such a fabric.
Known as a stain resistant treatment is water-and-oil repellent coating on a surface of a fabric, and known as a flame retardant treatment is flame retardant coating on a rear surface of a fabric.
JP-A-2017-196831 discloses a fabric at least to a front surface of which a fluorine-containing organic compound is attached and on a rear surface of which is layered a backing resin layer containing a resin, a flame retardant, and a fluorinated oil repellent agent.
The functions required of the functional fabric, however, are increasing every year, and required are a fabric that not only has flame retardancy and stain resistance but is also less likely to generate water spots, and a manageable fabric that allows pieces thereof to be easily separated from each other when the pieces are stacked and cut.
SUMMARY OF THE INVENTIONAn object of the present invention is to solve the above problems and to provide a fabric that has excellent stain resistance and excellent flame retardancy and that is less likely to generate water spots and is less likely to cause pieces thereof to attach to each other, and a method of manufacturing the fabric.
As a result of repetitive studies to solve the above problems, the present inventors have succeeded in solving the problems by selecting a flame retardant slightly soluble in water and selecting an acrylic resin having a prescribed glass-transition temperature as a binder resin of a coating layer, for forming the coating layer containing a fluorinated water-and-oil repellent agent and a flame retardant on one surface of a polyester fabric impregnated with a fluorinated water-and-oil repellent agent.
That is, a fabric according to the present invention is a polyester fabric impregnated with a fluorinated water-and-oil repellent agent, the fabric including a coating layer on one surface (preferably a rear surface) thereof, and the coating layer containing a fluorinated water-and-oil repellent agent, an organic phosphorus flame retardant having a solubility in water at 20° C. of 4% (4 g/100 g of water) or less, and an acrylic resin having a glass-transition temperature of −43° C. to −20° C.
Coating a fabric with a coating composition containing a flame retardant is capable of imparting flame retardant performance to the fabric, whereas the fabric is likely to generate a problem that the fabric is easily discolored by, for example, hot water or water spilled thereon and the fabric does not return to the original color even when dried (that is, the fabric is likely to generate water spots). In the present invention, however, an organic phosphorus flame retardant having a low solubility in water is used as the flame retardant to be capable of providing a fabric less likely to generate water spots.
Coating a fabric with a coating composition containing a water-and-oil repellent agent does not allow the coating composition to sufficiently infiltrate the fabric, causing a tendency to increase the thickness of a coating layer on a surface of the fabric. Therefore, when 10 to 20 pieces of the fabric are stacked and cut, the pieces of the fabric are attached to each other to be likely to generate a problem of having trouble peeling the pieces of the fabric after cutting. In the present invention, however, an acrylic resin having a glass-transition temperature of −43° C. to −20° C. is used as the binder resin to be capable of providing a fabric less likely to generate attachment between pieces of the fabric even at the time of processing the stacked pieces of the fabric.
Further, the coating layer preferably contains thermally expandable microcapsules that project from a surface of the coating layer to form projections and recesses (concavoconvex shape). Formation of the projections and recesses on the surface of the coating layer of the fabric reduces contact area between pieces of the fabric even when a plurality of pieces of the fabric are stacked, so that the pieces of the fabric are more easily separated from each other.
The amount, per unit area of the fabric, of the (dried) coating layer is preferably 70 g/m2 or less.
With the amount of the coating layer set at 70 g/m2 or less, the attachment property between pieces of the fabric is reduced to allow the pieces to be more easily separated from each other.
Further, the present invention is a method suitable for manufacturing the fabric, the method including the steps of:
(a) immersing a polyester fabric in a treatment liquid containing a fluorinated water-and-oil repellent agent to make the fabric contain the treatment liquid, and then drying the fabric;
(b) subjecting the fabric to hot water cleaning at a temperature of 65 to 90° C. or reduction cleaning; and
(c) coating one surface of the fabric with a coating composition containing a fluorinated water-and-oil repellent agent, an organic phosphorus flame retardant having a solubility in water at 20° C. of 4% or less, and an acrylic resin having a glass-transition temperature of −43° C. to −20° C., to form a coating layer.
Further, in the method, the coating composition used in the step (C) preferably contains thermally expandable microcapsules, and
the fabric is subjected to a heat treatment after the step (C) to expand the thermally expandable microcapsules contained in the composition and thus project the thermally expandable microcapsules from a surface of the coating layer.
According to the present invention, it is possible to provide a fabric that has high flame retardancy and stain resistance and that is less likely to generate water spots and cause pieces thereof to attach to each other, and a method of manufacturing the fabric.
DETAILED EXPLANATION OF THE PREFERRED EMBODIMENTSAs the degree of “stain resistance” of the fabric in the present invention, it is preferable that the fabric has an initial water repellency in accordance with JIS L1092 of 95 or higher as shown in the section of Examples and has no oil stain generated on front and rear surfaces of the fabric and on a soft wipe after 24 hours at 83° C. in a salad oil stain resistance test described in the section of Examples. The temperature 83° C. tends to lower an effect of the fluorinated water-and-oil repellent agent. The fabric satisfying the above standards, however, enables easy removal of stains caused by, for example, oily foodstuffs because even when salad oil is dropped onto a surface of the fabric and the fabric is then left at a temperature of 83° C., the fabric does not let the oil therethrough.
As the degree of “flame retardancy” of the fabric in the present invention, it is preferable that in a test performed in accordance with “Flammability of Interior Materials” specified in Federal Motor-Vehicle Safety Standard (FMVSS), the fabric is evaluated as “N” that is given when the fabric is not ignited even with 15-second flame application or when the fabric is ignited with the flame application but the flame is extinguished before crossing the marked line A (burning rate measuring start line), or the fabric is ignited with the flame application but has a burning rate of 101 mm/min or less after the flame crosses the marked line A. Particularly, the fabric is preferably evaluated as “N.”
As the degree of “water spots” of the fabric in the present invention, it is preferable as shown in the section of Examples that the fabric achieves grade 4 or higher in rating of water spots on a front surface of the fabric that is performed 24 hours after 4 mL of distilled water at 80° C. was dropped onto the front surface, a rear surface of the fabric is not wet, and the fabric achieves grade 4 or higher in rating of water spots on the rear surface of the fabric.
The degree of “attachment property” of the fabric in the present invention can be determined, as shown in the section of Examples, by confirming, when 20 pieces of the fabric are stacked and cut into a prescribed shape by a multi-ply cutting machine (NC cutting machine), whether or not the pieces of the fabric that form the cut stacked product attach to their upper and lower pieces of the fabric. Specifically, when the stacked product is divided into pieces, the number of pieces of the fabric that attach to their upper and lower pieces is preferably less than 10, more preferably 3.
In a fastness to rubbing test described in the section of Examples, the fabric according to the present invention preferably achieves grade 4 or higher in both dry and wet tests.
As a ground fabric used in the present invention, a polyester fabric is selected in terms of easily achieving the desired flame retardancy.
The polyester fabric in the present invention means a fabric containing polyester fiber, and may be not only a woven fabric, a knitted fabric, and a nonwoven fabric composed of polyester fiber alone but also any of a blended fabric, an interknitted fabric, and the like containing polyester fiber and other fibers (natural fibers such as cotton and wool, or chemical fibers such as a polyamide, rayon, and acrylic) in combination. The proportion of the polyester fiber in fibers constituting the fabric is preferably 60% by weight or more, more preferably 70% by weight or more, particularly preferably 80% by weight or more, further preferably 90% by weight or more. Particularly preferable is a fabric that is composed of polyester fiber and has a thickness of 0.2 to 3.0 mm (basis weight: 100 to 700 g/m2), in particular, a thickness of 0.4 to 2.6 mm (basis weight: 200 to 500 g/m2).
The ground fabric used in the present invention is preferably a polyester fabric impregnated with a fluorinated water-and-oil repellent agent. The fluorinated water-and-oil repellent agent is a compound that has a fluoroalkyl group obtained by substituting all or a part of hydrogen atoms in a hydrocarbon group with a fluorine atom(s). In the present invention, particularly, a polymer is preferably used that contains a monomer having a perfluoroalkyl group. From a viewpoint of environmental preservation and safety, the perfluoroalkyl group preferably has 6 carbon atoms. Examples of the fluorinated water-and-oil repellent agent that can be used in the present invention include a fluorinated water-and-oil repellent agent sold under the name of AsahiGuard E-SERIES from AGC Inc. and a fluorinated water-and-oil repellent agent sold under the name of NK GUARD S Series from NICCA CHEMICAL CO., LTD.
The fluorinated water-and-oil repellent agent used for immersing the fabric may be one agent or a plurality of agents (for example, two to three agents).
The fabric impregnated with the fluorinated water-and-oil repellent agent in the present invention means a fabric having the fluorinated water-and-oil repellent agent attached not only to a surface thereof but also to fibers therein.
As a method of impregnating the polyester fabric with the fluorinated water-and-oil repellent agent, it is possible to employ an immersion treatment generally called a padding treatment or a dip-nip treatment. For example, it is possible to obtain the fabric having the fluorinated water-and-oil repellent agent attached not only to a surface thereof but also to fibers therein (fabric impregnated with the fluorinated water-and-oil repellent agent) by preparing an aqueous treatment liquid containing the fluorinated water-and-oil repellent agent(s) (solid content) in an amount of 1.0 to 5.0% by weight, more preferably 1.5 to 4.0% by weight, immersing the polyester fabric in the treatment liquid (for example, 2 to 5 minutes) and squeezing the fabric with, for example, rollers (mangles) to make the entire fabric contain the treatment liquid, and then drying the fabric. Appropriate dry conditions are, for example, 110 to 170° C., in particular, 120 to 160° C. for about 1 to 5 minutes.
The amount of a fluorinated water-and-oil repellent agent(s) impregnated into the fabric by this stain resistant finish can be calculated by the concentration of the fluorinated water-and-oil repellent agent(s) in the treatment liquid and the squeezing rate. The impregnated amount, per unit area of the fabric, of the fluorinated water-and-oil repellent agent(s) contained in the dried fabric is appropriately 2.0 to 8.0 g/m2, more preferably 2.5 to 7.0 g/m2.
The fabric according to the present invention is preferably a fabric that has undergone a cleaning (reduction cleaning or cleaning with hot water) treatment after the stain resistant finish. The reduction cleaning is generally performed for a fiber product dyed at a high dye concentration to remove excess dye that causes, for example, color transfer, and the reduction cleaning is usually a step of placing a fiber product in an aqueous solution containing hydrosulfite and sodium hydroxide and cleaning the fiber product with the aqueous solution at around 80° C. (for example, 65 to 90° C., more preferably 70 to 85° C.). However, even when a fabric dyed at a high dye concentration is subjected to reduction cleaning after dyeing, the stain resistant finish allows the dye to easily exude from the fabric, deteriorating the fastness to rubbing of the fabric after the stain resistant finish (color transfer easily occurs). Therefore, a fabric dyed at a high dye concentration is preferably subjected to the reduction cleaning also after the stain resistant finish. Although the stain resistant finish tends to deteriorate (harden) texture of a fabric, cleaning improves the texture, so that it is preferable that a fabric free from the problem of fastness to rubbing (a fabric dyed at a low dye concentration) is also subjected to the cleaning treatment after the stain resistant finish. A fabric dyed at a low dye concentration may be cleaned with hot water (for example, 65 to 90° C., more preferably 70 to 85° C.) not by the reduction cleaning. For both the reduction cleaning and the hot water cleaning, the cleaning time can be set in the range of 1 to 60 minutes, for example, about 15 to 40 minutes.
It is possible to determine which is to be selected, the reduction cleaning or the hot water cleaning in the cleaning step after the stain resistant finish, with color transferability of the fabric as a guide (color transfer easily occurs in a fabric dyed at a high dye concentration and less occurs in a fabric dyed at a low dye concentration). Examples of the fabric dyed at a high dye concentration include a fabric dyed in black, blue, red, purple, dark gray, dark blue, or dark green at a dye concentration of about 5% owf or higher. Examples of the fabric dyed at a low dye concentration include a fabric dyed in white, light gray, beige, or cream at a dye concentration of less than about 5% owf. More specifically, a stain resistant-finished fabric having a fastness to rubbing of grade 4.0 or higher in both the dry and wet tests can be determined to need no reduction cleaning, and a stain resistant-finished fabric having a fastness to rubbing of lower than grade 4.0 can be determined to need the reduction cleaning. The fastness to rubbing is measured in accordance with JIS L0849 (Test methods for color fastness to rubbing).
The dry conditions after the cleaning can be set at, for example, 110 to 170° C., more preferably 120 to 160° C., in particular, 120° C. to 130° C. for about 1 to 5 minutes.
In the present invention, a coating layer containing a fluorinated water-and-oil repellent agent and a flame retardant is formed on one surface (in particular, a rear surface) of the stain resistant-finished ground fabric.
As the fluorinated water-and-oil repellent agent contained in the coating layer, it is possible to use those described above as the fluorinated water-and-oil repellent agent that can be used in the stain resistant finish. A fluorinated water-and-oil repellent agent may be used that is the same or different from that used in the stain resistant finish. One fluorinated water-and-oil repellent agent may be used alone or a plurality of fluorinated water-and-oil repellent agents may be used in combination.
The flame retardant contained in the coating layer is preferably an organic phosphorus flame retardant having a solubility in water at 20° C. of 4% (4 g/100 g of water) or less. Use of such a flame retardant makes the fabric less likely to generate water spots even after formation of the coating layer. As the organic phosphorus flame retardant, a flame retardant is exemplified that is selected from the group consisting of phosphonic acid esters, phosphoric acid amides, phosphoric acid ester amides, aromatic phosphoric acid esters, and halogen-containing phosphoric acid esters. One example of a preferable organic phosphorus flame retardant is a phosphonic acid ester-based flame retardant and/or melamine phosphate.
The coating layer may contain thermally expandable microcapsules. The thermally expandable microcapsules are usually formed of an outer envelope (shell) made from a thermoplastic resin, and a volatile liquid (usually a low-boiling-point liquid hydrocarbon such as isobutane and isopentane) included in the outer envelope. The thermally expandable microcapsules are heated to soften the thermoplastic resin constituting the outer envelope and increase the internal pressure by volatilization of the included liquid, thus expanding the microcapsules (making the microcapsules into balloon shapes). The microcapsules do not basically explode, and the weight thereof is the same between before and after the expansion. As such thermally expandable microcapsules, it is possible to use a commercially supplied product, for example, a product sold under the name of Matsumoto Microsphere from Matsumoto Yushi-Seiyaku Co., Ltd.
Unexpanded microcapsules are added to a composition for forming the coating layer of the present invention, and the fabric coated with the composition can be subjected to a heat treatment to expand the microcapsules and thus project a part of the microcapsules from a surface of the coating layer for formation of a concavoconvex surface. This reduces contact area between pieces of the fabric to make attachment between the pieces of the fabric less likely to occur even when a plurality of pieces of the fabric are stacked and cut after the formation of the coating layer on the fabric.
It is preferable to select, as the microcapsules, microcapsules having an unexpanded average particle size equal to or less than the application thickness during formation of the coating layer (thickness before volatilization of a solvent) and having an expanded average particle size of 20 μm or more (in particular, 30 μm or more) larger than the thickness of the coating layer (thickness after volatilization of a solvent). Selection of the thermally expandable microcapsules having such average particle sizes enables easy coating and sufficient inhibition of tack (attachment/adhesiveness).
It is possible to determine whether or not the expanded average particle size becomes 20 μm or more larger than the thickness of the coating layer by, for example, the thickness of the coating layer (after volatilization of a solvent) formed using a composition containing no thermally expandable microcapsules, and the expanded average particle size (or, for example, the thermal expansion rate) that is described in a product leaflet of the thermally expandable microcapsules. Usually, the thermal expansion rate differs depending on the heating temperature, so that the heating temperature can be adjusted to control the expanded average particle size.
Optimal ranges of the unexpanded and expanded average particle sizes of the microcapsules used in the present invention differ depending on the application thickness during formation of the coating layer and the thickness of the dried coating layer. The microcapsules, however, usually have an unexpanded average particle size of preferably 5 to 25 μm, more preferably 8 to 22 μm, particularly preferably 10 to 20 μm.
The microcapsules have an expanded average particle size of preferably 30 μm or more, more preferably 35 μm or more, particularly preferably 40 μm or more. An upper limit of the expanded average particle size is appropriately 80 μm or less, more appropriately 70 μm or less.
The content, per unit area of the fabric, of the fluorinated water-and-oil repellent agent(s) contained in the coating layer is preferably 0.5 to 4.0 g/m2, more preferably 0.7 to 3.5 g/m2, particularly preferably 1.0 to 3.0 g/m2. The content, per unit area of the fabric, of the flame retardant(s) contained in the coating layer is preferably 25 to 60 g/m2, more preferably 28 to 55 g/m2, particularly preferably 30 to 50 g/m2.
The content, per unit area of the fabric, of the thermally expandable microcapsules contained in the coating layer is preferably 1.5 to 4.0 g/m2, more preferably 1.8 to 3.5 g/m2, particularly preferably 2.0 to 3.0 g/m2.
The total amount, per unit area of the fabric, of the fluorinated water-and-oil repellent agent(s) impregnated into the fabric and the fluorinated water-and-oil repellent agent(s) contained in the coating layer is preferably 2.5 to 10.0 g/m2, more preferably 3.0 to 9.5 g/m2, particularly preferably 3.5 to 9.0 g/m2.
The coating layer of the present invention contains an acrylic resin having a glass-transition temperature of −43° C. to −20° C. as a binder resin for attaching (fixing) the fluorinated water-and-oil repellent agent and the flame retardant to the fabric. Using, as the binder resin, the acrylic resin having a glass-transition temperature of higher than −43° C. makes attachment between pieces of the fabric less likely to occur even after formation of the coating layer, and use of the acrylic resin having a glass-transition temperature of lower than −20° C. enables the fabric to retain soft texture. A more preferable acrylic resin is an acrylic resin having a glass-transition temperature of −41° C. to −30° C.
As such an acrylic resin, it is possible to use a product generally commercially supplied as a coating acrylic resin, for example, an acrylic resin sold under the trade name of Movinyl 7400 from Japan Coating Resin Co., Ltd. and an acrylic resin sold under the trade name of Newcoat FH from Shin Nakamura Chemical Co., Ltd.
The composition for forming the coating layer of the present invention may contain a thickener. As the thickener, it is possible to use, for example, an acrylic acid-based thickener, a urethane associative thickener, and a cellulose-based thickener. The attachment amount of the thickener to the fabric is usually about 0.5 to 5.0 g/m2.
The viscosity of the coating composition is appropriately about 20,000 to 70,000 mPa·s, particularly preferably 30,000 to 55,000 mPa·s. The viscosity of the coating composition in the present specification means viscosity measured using a B-type viscometer (BH type), at a measurement temperature of 20° C., with a rotor No. 6, at a rotation speed of 10 rpm, after 30 seconds from the start of the rotation.
The coating composition can be applied to the fabric using, for example, a knife coater, a comma coater, a bar coater, a die coater, a kiss-roll coater, or a gravure coater. The dry conditions after the application of the coating composition to the fabric can be set at, for example, 110 to 170° C., more preferably 120 to 160° C., in particular, 120° C. to 130° C. for about 2 to 5 minutes. When the coating composition contains the thermally expandable microcapsules, the microcapsules can be thermally expanded during this heating and drying.
The content, per unit area of the fabric, of the binder resin(s) contained in the coating layer is appropriately about 13 to 35 g/m2 (in particular, about 15 to 30 g/m2). When the thickener is an acrylic resin, the content of the binder and the thickener resin is preferably within the above range.
The amount, per unit area of the fabric, of the (dried) coating layer on the fabric is preferably 40 to 75 g/m2, more preferably 50 to 70 g/m2. With the amount of the coating layer set at particularly 70 g/m2 or less (in particular, 60 g/m2 or less), it is possible to further decrease the attachment property between pieces of the fabric. The coating layer containing the thermally expandable microcapsules, however, can reduce the attachment property between pieces of the fabric even when the amount of the coating is more than 70 g/m2. Accordingly, when the coating layer contains the thermally expandable microcapsules, the amount, per unit area of the fabric, of the (dried) coating layer may be about 45 to 90 g/m2 or about 50 to 80 g/m2.
In addition, the polyester fabric according to the present invention may have undergone dyeing and/or flame retardant finish before the stain resistant finish (impregnation with the fluorinated water-and-oil repellent agent). For example, it is possible to use a fabric subjected to the stain resistant finish after subjected to a dye treatment in a bath to which disperse dye is supplied or after subjected to flame retardant finish in a bath to which an organic phosphorus flame retardant is supplied. Regarding the amount of the flame retardant(s) (solid content) used for the in-bath finish, as owf (supply amount of the flame retardant relative to the weight of the fabric), it is appropriately 0.2 to 3.5% owf, in particular, about 0.4 to 3.0% owf, and as the attachment amount of the flame retardant to the fabric, it is appropriately 0.5 to 4.0 g/m2, in particular, about 1.0 to 3.0 g/m2.
The dyeing and the flame retarding may be performed in the same bath. In addition, a fabric dyed at a high dye concentration (about 5% owf or higher) in the dyeing may be subjected to the reduction cleaning after the dyeing.
Hereinafter, the present invention is described in further detail by way of comparative examples and examples. The present invention, however, is not to be limited to the examples.
EXAMPLESTo a bath were added black disperse dye (about 6.0% owf in terms of solid content) and 2.52% owf (in terms of solid content) of a phosphoric acid amide flame retardant sold under the trade name of Vigol FV-6010 from DAIKYO CHEMICAL CO., LTD., and a fabric was subject to dyeing and in-bath flame retardant finish simultaneously and then to reduction cleaning (80° C.×15 minutes) and drying. Then, the fabric was treated by the steps shown in Table 1.
In a stain resistant finish (step 1) by a dip-nip treatment, as the fluorinated water-and-oil repellent agent, a mixture of a fluorinated water-and-oil repellent agent sold under the name of AsahiGuard E-SERIES from AGC Inc. and a fluorinated water-and-oil repellent agent sold under the name of NK GUARD S Series from NICCA CHEMICAL CO., LTD. was used. A polyester fabric (polyester 100%: basis weight 280 g/m2) was immersed (at 150° C. for 2 minutes and 30 seconds) in an aqueous dispersion containing a total of 1.6 to 3.6% by weight (in terms of solid content) of the fluorinated water-and-oil repellent agents, and next, the immersed fabric was squeezed with mangles under a pressure of 3.0 kgf/cm2 (pick-up rate: 60%).
In a coating step (step 5), a rear surface of the fabric was coated, by a knife coater, with a coating composition having the viscosity thereof adjusted to a range of 30,000 to 35,000 mPa·s. Used as the thickener was Vanasol KB-660 (acrylic acid-based resin) sold from Shin-Nakamura Chemical Co., Ltd.
The flame retardant used in the coating was an inorganic phosphorus flame retardant (ammonium polyphosphate: APP) having a high solubility in water or an organic phosphorus flame retardant having a solubility in water at 20° C. of 4.0% or less. Used as the organic phosphorus flame retardant was a mixture of melamine phosphate (manufactured by Shin-Nakamura Chemical Co., Ltd.) and a phosphonic acid ester-based flame retardant sold under the name of SY-TC1 from SHINYO Co., Ltd. (weight ratio between active substances 1:1).
The fluorinated water-and-oil repellent agent used in the coating was a fluorinated water-and-oil repellent agent sold under the name of NK GUARD S-0545 from NICCA CHEMICAL CO., LTD.
The thermally expandable microcapsules used in the coating were thermally expandable microcapsules sold under the name of Microsphere F-50 from Matsumoto Yushi-Seiyaku Co., Ltd.
The acrylic resin used in the coating was an acrylic resin that was sold under the name of Movinyl 7400 from Japan Coating Resin Co., Ltd. and had a glass-transition temperature of −41° C., and the urethane resin used in the coating was a urethane resin sold under the name of SUPERFLEX E-2000 from DKS Co. Ltd.
Processed fabrics manufactured by the steps shown in Table 1 were then tested, according to the following methods, for their flame retardant performance, salad oil stain resistance, water repellency, water spot generating property, adhesiveness and adhesion during cutting, and fastness to rubbing.
Flame Retardant Performance
A test was performed in accordance with “Flammability of Interior Materials” specified in Federal Motor-Vehicle Safety Standard (FMVSS), and flame retardant performance was determined.
The evaluation “N” was given to a test piece (processed fabric) that was not ignited even with 15-second flame application or that was ignited with the flame application but the flame was extinguished before crossing the marked line A. When a test piece was ignited and the flame crossed the marked line A, the burning time and the burned distance were recorded and the burning rate (mm/min) was calculated. The test was performed using, as the test piece, 3 test pieces of each cut out along the long axis (vertical) and along width (horizontal) of the processed fabrics (the table shows the result of the worst piece among 6 test pieces).
Salad Oil Stain Resistance Test
One test piece with an about 10×10 cm square was prepared from each of the samples (processed fabrics). A soft wipe (Elleair Prowipe) was placed on a tray, and the test piece was put on the soft wipe (a coated test piece was put on the soft wipe with its coated surface (rear surface) downward). Salad oil was dropped in 5 spots on the test piece with a dropper such that each droplet had a diameter of about 5 mm or 0.05 mL.
The tray was left to stand in a Geer oven at 83° C. for 24 hours. After 24 hours, the tray was taken out and then the test piece was observed whether a front surface thereof was wet at the salad oil-dropped spots (whether an oil stain was generated) and whether an oil stain due to the salad oil was present on the rear surface thereof and the soft wipe. A test piece was determined to be passed (0) that had no oil stain on the front and rear surfaces thereof and on the soft wipe placed underneath the test piece.
Water Repellency
A test piece cut in a size of 20 cm×20 cm was fixed to a test piece holding frame in a device specified in JIS L1092 6.2 so as not to generate wrinkles on the test piece.
Into a funnel was poured 250 mL of distilled water or ion-exchange water, and the distilled water or the ion-exchange water was sprayed onto the test piece.
Next, the frame with the test piece was removed from a support, held horizontally on one end of the frame, and tapped once against a solid object on the other end of the frame, with a front side of the test piece downward. The frame with the test piece was further rotated by 180° and the same procedure as above was performed to remove excess water droplets.
The wetting state of the test piece still fixed to the frame was rated.
0 point: showing wetting on the entire front and rear surfaces
50 points: showing wetting on the entire front surface
70 points: showing wetting in half of the front surface, with discrete small wet areas penetrating the fabric
80 points: showing small discrete water droplet-shaped wet areas on the front surface
90 points: showing no wetting on the front surface, with small water droplets attached to the front surface
95 points: showing no wetting on the front surface, with small water droplets slightly attached to the front surface
100 points: showing neither wetting on the front surface nor water droplets attached to the front surface
A test piece having an initial water repellency of 95 points or higher was evaluated as passed.
Water Spots
Distilled water at 80° C. in an amount of 4 mL was dropped onto a front surface of the processed fabric, which was naturally dried for 24 hours. Then, the fabric was rated according to the following criteria by confirming the presence or absence of water spots (discoloration) on front and rear surfaces thereof and wetting on the rear surface. Evaluated as passed (∘) was a fabric with the front surface rated as grade 4 or higher and the rear surface rated as grade 4 or higher and having no wetting thereon.
Grade: Criterion
Grade 5: no discoloration
Grade 4: almost unrecognizable discoloration
Grade 3: slightly recognizable discoloration
Grade 2: easily recognizable discoloration
Grade 1: significant discoloration
Adherence and Adhesion During Cutting
Twenty test pieces (about 1.5 m×about 5 m) were prepared from each of the samples (processed fabrics), all stacked, and cut into a prescribed shape by a multi-ply cutting machine (NC cutting machine). After the cutting, when the stacked product (stacked product formed of 20 test pieces) cut in the prescribed shape was divided into pieces, the number of test pieces was counted that were not divided into individual test pieces but remained bonded to another test piece.
Fastness to Rubbing
Each of the processed fabrics was subjected to a dry test (DRY) and a wet test (WET) in accordance with JIS L0849 (Test methods for color fastness to rubbing). The determination of staining was performed with a gray scale for assessing staining (JIS L0805), to determine one of grades 1 to 5.
Table 1 shows the processing steps and the performance of the processed fabrics and Table 2 shows the amount of solid content of each component attached to the ground fabric by the dip-nip step and the coating step (unit: g/m2).
As shown in Table 1, the blank fabric (fabric only subjected to the dyeing, in-bath flame retardant treatment, and reduction cleaning) had a bad result in the salad oil stain resistance test. On the other hand, the fabric (No. 1) further subjected to the dip-nip processing with the aqueous dispersion containing the fluorinated water-and-oil repellent agent had good results in the salad oil stain resistance test and the water repellency test but decreased in flame retardancy and fastness to rubbing. On the other hand, the fabric (No. 2) subjected to the reduction cleaning after the dip-nip treatment improved in fastness to rubbing to have grade 4 in DRY and WET but was still insufficient in flame retardant performance. Further, the fabric (No. 3) that was subjected to the dip-nip treatment and the reduction cleaning and then had a flame retardant back coating layer (BC1) formed on a rear surface thereof was evaluated as “N” in flame retardant performance, but generation of an oil stain was confirmed in the salad oil stain resistance test and the degree of water spots was worsened. Next, as regards the fabrics (Nos. 4 to 6) that were subjected to the dip-nip treatment and the reduction cleaning and then had a flame retardant and stain resistant back coating layer (BC2) formed thereon with a composition containing ammonium polyphosphate (APP) as the flame retardant and the urethane resin as the binder resin and further containing the fluorinated water-and-oil repellent agent, the fabrics were evaluated as “N” in flame retardant performance and achieved the acceptance criteria in the salad oil stain resistance test and water repellency, but the fabrics still had an undesirable degree of water spots and significantly increased the adhesiveness during the cutting (all the 20 test pieces were attached to each other to form a bundle).
In contrast, as regards the fabrics (Nos. 7 to 9) that had a back coating layer (BC3) formed on a rear surface thereof, the back coating layer containing the fluorinated water-and-oil repellent agent, the organic phosphorus flame retardant having a solubility in water of 4% or less, and the acrylic resin having a glass-transition temperature of −41° C. as the binder resin, the fabrics were capable of achieving the desired characteristics in all of flame retardancy, salad oil stain resistance, water repellency, and water spot inhibiting performance, and the fabrics remarkably decreased the adhesiveness during the cutting in comparison with the case of using the urethane resin. Particularly, the fabrics (Nos. 8 and 9) whose amount, per unit area of the fabric, of the coating layer was adjusted to 70 g/m2 or less was further reduced in attachment property during the cutting. It was confirmed that when the binder resin was replaced by acrylic resin having glass-transition temperature of −45° C. or −50° C., the adhesiveness during the cutting tended to increase according as the glass-transition temperature was low. The acrylic resin having an excessively high glass-transition temperature, however, was confirmed to harden the coating layer, exhibiting a tendency to also harden the texture of the fabric. Therefore, an acrylic resin having a glass-transition temperature in the range of −43° C. to −20° C. was appropriately used as the binder resin used in the coating layer. It was confirmed that using a polyester resin as the binder resin tended to increase the attachment property of the fabric as in the case of using the urethane resin. This tendency is considered to be due to the fact that the polyester resin was melted with heat during the cutting of the fabric by the NC cutting machine and showed hot-melt adhesive agent-like characteristics.
As regards the fabric (No. 10) that had a back coating layer (BC4) formed thereon using a composition to which the thermally expandable microcapsules were further added, the fabric was capable of retaining the desired characteristics in all of flame retardancy, the salad oil stain resistance test, water repellency, and water spot inhibiting performance, and the number of test pieces was 0 that bonded to another test piece after the cutting.
The experiments demonstrated that in order to obtain a fabric that not only has desired flame retardancy and stain resistance but is also less likely to generate water spots and cause pieces thereof to attach to each other, it is effective to form a coating layer containing a fluorinated water-and-oil repellent agent and a flame retardant on one surface of a fabric impregnated with a fluorinated water-and-oil repellent agent, to use an organic phosphorus flame retardant having a low solubility in water as the flame retardant, and to use an acrylic resin having a glass-transition temperature of −43° C. to −20° C. as a binder resin.
Further, it was confirmed that the attachment property of the fabric can be further reduced by reducing the amount of the coating layer or by adding thermally expandable microcapsules to the coating composition to form projections and recesses on a surface of the coating layer.
The fabric according to the present invention has excellent flame retardancy and stain resistance and is less likely to generate water spots, so that it is suitably used as an interior fabric for vehicles such as a car. Further, the fabric according to the present invention is less likely to cause pieces thereof to attach to each other even when the pieces are stacked, so that the fabric is excellent in processability when layered pieces thereof are subjected to, for example, cutting.
Claims
1. A fabric being a polyester fabric impregnated with a fluorinated water-and-oil repellent agent, the fabric comprising a coating layer on one surface thereof,
- the coating layer containing a fluorinated water-and-oil repellent agent, an organic phosphorus flame retardant having a solubility in water at 20° C. of 4% or less, and an acrylic resin having a glass-transition temperature of −43° C. to −20° C.
2. The fabric according to claim 1, wherein the coating layer is formed on a rear surface of the fabric.
3. The fabric according to claim 1, wherein the coating layer further contains thermally expandable microcapsules that project from a surface of the coating layer to form projections and recesses.
4. The fabric according to claim 1, wherein an amount, per unit area of the fabric, of the coating layer is 70 g/m2 or less.
5. A method of manufacturing a fabric, the method comprising the steps of:
- (a) immersing a polyester fabric in a treatment liquid containing a fluorinated water-and-oil repellent agent to make the fabric contain the treatment liquid, and then drying the fabric;
- (b) subjecting the fabric to hot water cleaning at a temperature of 65 to 90° C. or reduction cleaning; and
- (c) coating one surface of the fabric with a coating composition containing a fluorinated water-and-oil repellent agent, an organic phosphorus flame retardant having a solubility in water at 20° C. of 4% or less, and an acrylic resin having a glass-transition temperature of −43° C. to −20° C., to form a coating layer.
6. The method according to claim 5, wherein the coating composition used in the step (C) further contains thermally expandable microcapsules, and
- the method comprises, after the step (C), a step of expanding the thermally expandable microcapsules contained in the composition by a heat treatment to project the thermally expandable microcapsules from a surface of the coating layer.
7. The fabric according to claim 2, wherein the coating layer further contains thermally expandable microcapsules that project from a surface of the coating layer to form projections and recesses.
8. The fabric according to claim 2, wherein an amount, per unit area of the fabric, of the coating layer is 70 g/m2 or less.
9. The fabric according to claim 3, wherein an amount, per unit area of the fabric, of the coating layer is 70 g/m2 or less.
10. The fabric according to claim 7, wherein an amount, per unit area of the fabric, of the coating layer is 70 g/m2 or less.
Type: Application
Filed: Feb 1, 2019
Publication Date: Sep 12, 2019
Inventors: Rie HAYASHI (Saitama), Chika NEMOTO (Saitama), Kohei OHARA (Shiga), Takayuki OISHI (Shiga), Tatsuya FUKUI (Shiga)
Application Number: 16/265,976
