JP2010018894A - Primary backing fabric for tufted carpet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a primary backing fabric for tufted carpets which is a filament nonwoven fabric using a polylactic acid-based polymer applicable to a primary backing fabric for tufted carpets and has heat stability and heat resistance. <P>SOLUTION: The primary backing fabric for tufted carpets is formed from a filament nonwoven fabric in which conjugate filaments obtained by combining a crystalline aromatic polyester copolymer having a melting point of 180-230°C, being a polymer comprising an alkylene terephthalate as a main repeating unit and copolymerized with an aromatic dicarboxylic acid or an aliphatic diol, with a polylactic acid-based polymer, are used as constituent filaments, and the conjugate filaments are assembled. The conjugate filaments have a single filament fineness of 5-12 decitex, the conjugate filaments constituting the filament nonwoven fabric are mutually heat-bonded by at least softening of the polylactic acid-based polymer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a primary base fabric for tufted carpet.

  In recent years, synthetic fibers using petroleum as a raw material have a large amount of heat generated during incineration, and therefore need to be reviewed from the viewpoint of protecting the global environment. In view of this, fibers made of aliphatic polyester that biodegrades in nature have been developed and are expected to contribute to environmental protection. Among aliphatic polyesters, a polylactic acid polymer that is a plant-derived polymer and does not use petroleum as a raw material has a relatively high melting point, and is expected to be used in a wide range of fields. In addition, polylactic acid polymers have the best mechanical properties and cost balance among biodegradable polymers. Along with this, development of fibers using this has been carried out at a rapid pace.

  However, the most promising polylactic acid polymer also has a problem that it is inferior in high-temperature mechanical properties. Here, when the polylactic acid polymer is inferior in high-temperature mechanical properties, the polymer is drastically deteriorated when the polylactic acid polymer is placed at a high temperature, that is, above 60 ° C., which is the glass transition temperature (Tg) of the polylactic acid polymer. Refers to softening. Actually, when a tensile test of a long-fiber nonwoven fabric made of a polylactic acid-based polymer is performed by changing the atmospheric temperature, it has been found that the strength of the long-fiber nonwoven fabric rapidly decreases at 70 ° C. or higher. Therefore, a long-fiber nonwoven fabric made of a polylactic acid-based polymer is inferior in mechanical properties at high temperatures, so there is no problem when used at room temperature, but deformation and sag occur in a high-temperature atmosphere.

  On the other hand, it is known to use a nonwoven fabric in which long fiber groups are accumulated as a primary base fabric for tufted carpet. This primary base fabric is used as a support when tufting pile yarn (planting pile yarn), and in the carpet manufacturing process, the primary base fabric is tufted using the desired pile yarn. A carpet is obtained by obtaining a raw machine and performing a backing process, and the obtained carpet is subjected to desired molding as necessary.

  The backing process is usually a process in which a hot-melted backing material is laminated or coated, and then dried in an oven to harden the backing material. The primary base fabric is in contact with the hot-melted backing material. High heat is applied, and heat is also applied in the subsequent drying step. Therefore, the primary base fabric is required to have thermal stability that can withstand high heat in the backing process and is not easily thermally deformed.

  As described above, the long-fiber nonwoven fabric made of a polylactic acid-based polymer is inferior in mechanical properties at high temperatures, so when applied to a primary base fabric for carpets, it is not suitable for heat, self-weight, and stress applied in the backing process. There are problems such as deformation that cannot be tolerated.

In order to solve the above-described problems in the long-fiber nonwoven fabric made of a polylactic acid-based polymer, the present applicant has arranged a specific polymer and a polylactic acid-based polymer in a specific position and combined them to provide heat resistance. The fiber which improved the property is proposed (patent document 1).
JP 2005-206984 A

  The present invention is a long-fiber nonwoven fabric using a polylactic acid-based polymer that can be applied to a primary fabric for carpets, and can have thermal stability and heat resistance by means other than the method proposed above. It is to provide a primary base fabric for tufted carpet.

  That is, the present invention relates to a polymer obtained by copolymerizing an alkylene terephthalate as a main repeating unit and an aromatic dicarboxylic acid or an aliphatic diol, a crystalline aromatic polyester copolymer having a melting point of 180 to 230 ° C., and a polylactic acid-based polymer. A composite comprising a composite long fiber combined with a composite as a constituent fiber, constituted by a long fiber nonwoven fabric in which the composite long fibers are accumulated, and a single filament fineness of the composite long fiber is 5 to 12 dtex, and constitutes a long fiber nonwoven fabric The gist of the primary fiber for tufted carpet is that the long fibers are thermally bonded by at least softening of the polylactic acid polymer.

  Hereinafter, the present invention will be described in detail.

  The primary base fabric for tufted carpet according to the present invention comprises, as a constituent fiber, a composite long fiber in which a crystalline aromatic polyester copolymer and a polylactic acid polymer are combined.

  The aromatic polyester copolymer used in the present invention is a polymer having a melting point of 180 to 230 ° C. and having an alkylene terephthalate as a main repeating unit and an aromatic dicarboxylic acid or an aliphatic diol copolymerized.

  Examples of the alkylene terephthalate include alkylene terephthalates such as ethylene terephthalate, butylene terephthalate, and trimethylene terephthalate. Examples of the aliphatic dicarboxylic acid copolymerized with the alkylene terephthalate include isophthalic acid and 5-sulfoisophthalic acid. Examples of the aliphatic diol include ethylene glycol, propylene glycol, 1,4-butanediol, and 1,4. -Cyclohexanedimethanol and the like. In the present invention, a copolymer formed by copolymerizing isophthalic acid with ethylene terephthalate as the main repeating unit, or a copolymer formed by copolymerizing butanediol with ethylene terephthalate as the main repeating unit is preferably used. it can.

  Since the aromatic polyester copolymer used in the present invention is crystalline, it has a clear crystal melting point (showing a clear melting point peak when a melting endothermic curve is drawn). A fiber having a coalescence as a skeleton component hardly undergoes thermal shrinkage when heat is applied. Therefore, the fibers are not thermally shrunk by the heat bonding treatment when the nonwoven web made of the fibers is subjected to the heat bonding treatment to obtain a nonwoven fabric, and the dimensional stability is good. Further, the obtained non-woven fabric has little decrease in fiber strength and elongation even under a high temperature atmosphere, and can maintain stable quality.

  The melting point of the aromatic polyester copolymer is 180 to 230 ° C. By setting the melting point to 230 ° C. or lower, the spinning temperature at the time of composite spinning can be set to 250 ° C. or lower, and the polylactic acid polymer is not thermally decomposed during the composite spinning, so that the spinning property is improved. Moreover, by setting the temperature to 180 ° C. or higher, it is possible to maintain high crystallinity of the polymer, to obtain fibers and nonwoven fabrics having heat resistance and thermal stability, and heat shrinkage during heat treatment hardly occurs, Mechanical properties that can withstand a backing process in which high-temperature heat is applied in the production of carpets and a molding temperature (about 130 to 140 ° C.) when a molded carpet is obtained can be maintained.

In the case of a polyester copolymer obtained by copolymerizing an aromatic dicarboxylic acid, the melt viscosity of the aromatic polyester copolymer is 1000 to 2,000 dPa · s at a spinning temperature and a shear rate of 1,000 seconds ^−1. Preferably, in the case of a polyester copolymer obtained by copolymerizing an aliphatic diol, the melt viscosity at a spinning speed of 1000 sec- ^{1 at} the spinning temperature is preferably 1000 to 3000 dPa · s. By using such a low-viscosity polymer, it is possible to improve the crystallinity of the fiber obtained by melt spinning at a high speed, and to obtain a nonwoven fabric with smaller thermal shrinkage and excellent thermal stability. In addition, since it is better that the difference in melt viscosity between the aromatic polyester copolymer and the polylactic acid polymer at the spinning temperature is smaller, the melt viscosity at a shear rate of 1000 sec- ¹ at the spinning temperature of the polylactic acid polymer is also 1000. It is preferably in the range of ˜2000 dPa · s.

  The polylactic acid polymer used in the present invention includes poly-D-lactic acid, poly-L-lactic acid, a copolymer of D-lactic acid and L-lactic acid, a copolymer of D-lactic acid and hydroxycarboxylic acid, L -A copolymer of lactic acid and hydroxycarboxylic acid, a polymer selected from the group consisting of a copolymer of D-lactic acid, L-lactic acid and hydroxycarboxylic acid, or a blend thereof. Examples of the hydroxycarboxylic acid for copolymerizing the hydroxycarboxylic acid include glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxypentanoic acid, hydroxycaproic acid, hydroxycaproic acid, hydroxyoctanoic acid, etc. Hydroxycaproic acid and glycolic acid are preferable from the viewpoint of cost reduction.

  In the present invention, a polylactic acid polymer having a melting point of 150 ° C. or higher or a polymer blend having a melting point of 150 ° C. or higher may be used. Since the polylactic acid polymer having a melting point of 150 ° C. or higher has high crystallinity, it becomes a non-woven fabric excellent in heat resistance, and heat treatment can be stably performed.

  The melting point of poly-L-lactic acid and poly-D-lactic acid, which are homopolymers of polylactic acid, is about 180 ° C. When not a homopolymer but a copolymer is used as the polylactic acid polymer, the copolymerization ratio of the monomer components is determined so that the melting point of the copolymer is 150 ° C. or higher. In the case of a copolymer of L-lactic acid and D-lactic acid, the copolymerization ratio of L-lactic acid and D-lactic acid is a molar ratio of (L-lactic acid) / (D-lactic acid) = 5/95. ˜0 / 100 or (L-lactic acid) / (D-lactic acid) = 95/5 to 100/0. If the copolymerization ratio is out of the above range, the melting point of the copolymer becomes less than 150 ° C., the amorphousness becomes high, and the object of the present invention cannot be achieved.

  Other components may be blended with the polylactic acid polymer. Examples of other components include aliphatic polyester copolymers (for example, trade name “GSPla” manufactured by Mitsubishi Chemical Corporation) having aliphatic diol, aliphatic dicarboxylic acid, and aliphatic hydroxycarboxylic acid as constituent components, Biodegradable aliphatic-copolymerized aromatic polyester polymer obtained by condensing diol, aromatic carboxylic acid and aliphatic dicarboxylic acid (for example, product name “Easter Bio GP” manufactured by Novamont, manufactured by BASF Product name "ECOFLEX").

  In the polymer constituting the composite long fiber of the present invention, a pigment, a heat stabilizer, an antioxidant, a weathering agent, a flame retardant, a terminal blocker, a plasticizer, a lubricant, as long as the object of the present invention is achieved. Release agents, antistatic agents, fillers, and the like may be added. For example, it is preferable to blend talc as a crystal nucleating agent.

  The composite form of the composite long fiber in the present invention is preferably such that the polylactic acid polymer forms a part of the fiber surface as a form in which the polylactic acid polymer can function as a thermal adhesive component. A more preferable form is a core-sheath type in which an aromatic polyester copolymer forms a core and a polylactic acid polymer forms a sheath, or an aromatic polyester copolymer forms a core and polylactic acid. It is a multi-leaf type in which a plurality of protruding leaf portions are formed so that the system polymer surrounds the outer periphery of the core portion. The core-sheath type or multi-leaf type. By adopting a core-sheath type or a multi-leaf type, it is possible to easily perform a heat bonding treatment for causing the polylactic acid polymer to function as a heat bonding component.

  The composite ratio (mass ratio) of the aromatic polyester copolymer and the polylactic acid polymer in the composite long fiber is polylactic acid polymer / aromatic polyester copolymer = 3/1 to 1/3. preferable. By setting the ratio of the polylactic acid polymer / aromatic polyester copolymer to 3/1 or less, the mechanical strength of the resulting nonwoven fabric at a high temperature can be sufficiently maintained, and the polylactic acid polymer / By setting the ratio of the aromatic polyester copolymer to 1/3 or more, it can sufficiently function as a thermal adhesive for the polylactic acid polymer, and the shape retention of the nonwoven fabric becomes good.

  The single yarn fineness of the composite long fiber is 5 to 12 dtex. By adopting a relatively large fineness such as a single yarn fineness of 5 to 12 dtex, the fiber itself is not easily damaged when the pile yarn is driven into the base fabric. In addition, by setting the single yarn fineness to 5 dtex or more, the fibers in the thickness direction (surface layer and inner layer) of the nonwoven fabric can sufficiently retain the fiber form, and the planted pile yarn can be satisfactorily gripped. That is, when the single yarn fineness is less than 5 dtex, the heat tends to be transferred to the fibers during the heat bonding process when the fibers are heat bonded, and the fibers in the entire thickness direction tend to be heat-sealed over the entire surface of the nonwoven fabric. Thus, the fiber form cannot be maintained well, the pile yarn thus planted cannot be gripped well, and the tuft retention tends to be poor. On the other hand, when the single yarn fineness exceeds 12 dtex, in the melt spinning process, the spinning yarn is inferior in cooling property, and the yarns are easily adhered to each other.

  The composite long fibers constituting the long fiber nonwoven fabric in the present invention are thermally bonded by at least softening of the polylactic acid polymer. In thermal bonding, at least the polylactic acid polymer at the part where heat and pressure are applied is softened at least by the heat-embossing of the polylactic acid polymer at the contact between the constituent fibers. The thing etc. which heat-bonded fiber by the thing etc. are mentioned. When the fibers are thermally bonded to each other, the mechanical strength and form stability can be satisfactorily maintained as a non-woven fabric, and can sufficiently withstand winding during the manufacturing process. The form of the long-fiber nonwoven fabric in which the composite long fibers are thermally bonded to each other is such that both surface layers are thermally bonded to each other by softening of the polylactic acid polymer, and the inner layer is generally not thermally bonded to the composite long fibers. It exists in a fiber aggregate or is thermally bonded, but it becomes a temporary bonded state in which the bonded state is released and physical fibers such as a tufting process are released and the separated fibers are accumulated. It may be what you have. By holding the fiber form of the composite long fiber of the inner layer, the pile yarn can be favorably gripped as a primary base fabric for tufted carpet.

The primary base fabric for tufted carpet of the present invention preferably has a basis weight of 80 to 150 g / m ² , more preferably 100 to 120 g / m ² . If the basis weight is less than 80 g / m ^2, when using a tufted primary backing for carpets of the present invention as a molding carpet, tear is likely to occur during molding. On the other hand, if the basis weight exceeds 150 g / m ² , the amount of fibers is too large, and the pile height is likely to be non-uniform or the tuft spacing is likely to be uneven. It is also disadvantageous in terms of cost.

  If necessary, the primary base fabric for tufted carpet of the present invention may be provided with a binder resin, and the constituent fibers may be bonded together with the binder resin. As a binder resin, the same thing as the polylactic acid-type polymer which comprises the nonwoven fabric mentioned above can be used conveniently. Polysaccharides such as polyvinyl alcohol and natural starch such as starch, protein, chitosan and the like may also be used. In addition, a desired molar ratio can be obtained by combining two or more conventionally used monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, acrylonitrile, and styrene. Copolymers copolymerized with can also be employed. Moreover, you may use the bridge | crosslinking type binder resin which bridge | crosslinked these copolymers with crosslinking agents, such as a melamine resin and a phenol resin. The adhesion amount of the binder resin is preferably 20% by mass or less with respect to the fiber mass.

  The primary base fabric for tufted carpet of the present invention preferably has a dry heat shrinkage rate at 140 ° C. for 5 minutes of 5% or less in both the vertical and horizontal directions. By setting the dry heat shrinkage rate to 5% or less, a tufted carpet with small shrinkage can be obtained in the backing process described later. The reason why the dry heat shrinkage rate is evaluated at 140 ° C. is because the case where the backing material is formed of a biodegradable material is taken into consideration. The biodegradable resin used as the backing material preferably has a melting point of 80 to 130 ° C. When providing the backing material, the high temperature molten backing material is usually extruded and bonded to the base fabric in the molten state. When the melting point of the backing material exceeds 130 ° C., the temperature of the molten backing material is 160. It is not preferable because the polylactic acid-based polymer constituting the base fabric is melted or softened when the backing material is bonded, and damage to the base fabric increases. . On the other hand, when the melting point is less than 80 ° C., for example, when the carpet using the primary base fabric for tufted carpet of the present invention is used for an automobile option mat or the like, the backing material melts due to the temperature in the automobile room under hot weather. Or it may be softened.

  In the present invention, a tufted carpet can be obtained by planting pile yarn on the above-mentioned primary base fabric for tufted carpet.

  Moreover, it is preferable that the backing material provided on the surface opposite to the pile surface of the tufted carpet is formed of a biodegradable resin having a melting point of 80 to 130 ° C. as described above. An example of the biodegradable resin is a polylactic acid polymer composed of a copolymer of L-lactic acid and D-lactic acid. In this case, the copolymerization ratio of L-lactic acid and D-lactic acid is (L-lactic acid) / (D-lactic acid) = 8/92 to 12/88 or (L-lactic acid) / (D -Lactic acid) = 88/12 to 92/8 is preferable. In addition, as a biodegradable resin, an aliphatic polyester copolymer (trade name “GSPla” manufactured by Mitsubishi Chemical Corporation) having an aliphatic diol, an aliphatic dicarboxylic acid and an aliphatic dihydroxycarboxylic acid as constituents, an aliphatic diol, Biodegradable aliphatic-aromatic copolymerized polyester copolymer obtained by condensing carboxylic acid with aromatic carboxylic acid and aliphatic dicarboxylic acid (trade name “Easter Bio GP”, manufactured by Novamont, ECOFLEX ") and the like.

  The primary base fabric for tufted carpet of the present invention can be efficiently produced by obtaining a long fiber nonwoven fabric by a spunbond method.

  First, a polylactic acid polymer and the above-described aromatic polyester copolymer are prepared. Each of the prepared polymers is weighed individually and melt-spun using a desired composite spinneret. In the present invention, the aromatic polyester copolymer forms the core, and the polylactic acid polymer melt-spins through a core-sheath type composite spinneret that forms the sheath, or the aromatic polyester copolymer The coalescence forms a core portion, and the polylactic acid polymer is melt-spun through a multileaf composite spinneret that constitutes a leaf portion. The spun yarn is cooled using a conventionally known cooling device such as a horizontal spraying or an annular spraying, and then pulled and pulled using a pulling device such as an air jet.

  The towing speed when towing is preferably 3500 to 5500 m / min. When the pulling speed is less than 3500 m / min, the molecular orientation is not sufficiently promoted in the yarn, and the resulting long fiber nonwoven fabric tends to be inferior in dimensional stability and thermal stability. On the other hand, if the pulling speed is too high exceeding 5500 m / min, the spinning stability is poor.

  The stretched long fibers are spread with a known spreader and then spread on a movable collection surface such as a screen conveyor to form a nonwoven web in which the constituent fibers are randomly deposited. . Next, the primary base fabric for tufted carpet of the present invention is obtained by subjecting the web to a thermal bonding treatment. Examples of the thermal bonding treatment method include a hot air treatment method, a hot pressure welding method through a hot pressure welding device, and the like. Examples of the heat pressure welding apparatus include an embossing roll and a flat roll, a pair of embossing rolls, and a pair of flat rolls. A combination of a plurality of these heat pressure welding devices may be used. In the present invention, it is preferable to perform hot embossing using an embossing roll.

  When performing the thermal welding, it is important to appropriately select the thermal welding temperature (roll set temperature) and the linear pressure between the rolls. The hot pressing temperature is preferably (Tm−90) ° C. to (Tm−60) ° C., where Tm is the melting point of the polylactic acid polymer. If the hot pressing temperature is set to a temperature lower than (Tm-90) ° C., depending on the processing speed, the polylactic acid polymer is not sufficiently softened, and the fibers cannot be sufficiently thermally bonded, resulting in a primary group to be obtained. The mechanical performance of the fabric is inferior. On the other hand, when the hot pressing temperature is set to a high temperature exceeding (Tm-60) ° C., the softened polylactic acid-based polymer is fused to the roll, and the operability tends to be remarkably impaired. In addition, due to the influence of heat, the resulting primary base fabric becomes heat-cured rough or rigid, or heat is transferred to the inner layer of the primary base fabric, and the constituent fibers are fused together as a whole. When tufting, the penetration resistance of the tuft needle increases, or the tuft retention tends to be inferior.

  The linear pressure between the rolls during the heat-welding process is preferably about 90 to 300 N / cm. By setting it to 90 N / cm or more, the polylactic acid-based polymer can be sufficiently softened to function as an adhesive, and by setting it to 300 N / cm or less, heat is transmitted to the inner layer too much and the entire nonwoven fabric is The fiber form can be sufficiently retained without being fused.

When an embossing roll is used, the part of the web that comes into contact with the convex portion of the embossing roll during the heat-welding process becomes the heat-welding part. It is preferable to use an embossing roll in which the convex portion interview is in a range of 4% or more with respect to the area of the entire embossing roll. If it is less than 4%, the area that is heat-welded to the entire area of the nonwoven fabric is so small that it is difficult to expect the strength required for a base fabric for tufted carpet, and tufting, dyeing, backing It becomes difficult to obtain the required strength against the tensile stress during secondary processing such as. The upper limit of the area of the hot press contact part is preferably about 50%. The density of the pressure contacts is preferably ²⁰ to 65 / cm ² . Although the shape of the front-end | tip part of the convex part of an embossing roll turns into the shape of a heat press-contact part, this shape is not specifically limited. For example, various shapes such as a round shape, an oval shape, a rhombus shape, a triangle shape, a T shape, a well shape, a rectangular shape, and a square shape can be adopted. The tip part area of this convex part should just be about 0.1-1.0 mm < ² >.

  A binder resin is imparted to the primary base fabric of the present invention as necessary. When the binder resin is applied, the binder resin may be applied after the constituent fibers are thermally bonded to each other by a thermal bonding process. In other words, a binder resin solution emulsified and dispersed in water is impregnated with a non-woven fabric that has been subjected to a thermal bonding treatment and dried, or a binder resin solution is applied to the nonwoven fabric that has been subjected to a thermal bonding treatment by a method such as spraying. A method of performing a drying treatment can be employed. As described above, the adhesion amount of the binder resin is preferably 20% by mass with respect to the fiber mass.

  The primary base fabric for tufted carpet of the present invention is composed of a long-fiber nonwoven fabric, and the fibers constituting the long-fiber nonwoven fabric are composed of a polylactic acid polymer and an alkylene terephthalate containing an aromatic dicarboxylic acid or an aliphatic diol. It is a fiber in which a copolymerized aromatic polyester copolymer having a melting point of 180 to 230 ° C. is composited. According to the primary base fabric for tufted carpet of the present invention, the aromatic polyester copolymer has high crystallinity, and this maintains the fiber form as the fiber skeleton, and the polylactic acid-based polymer on the fiber surface. Fibers are heat-bonded, and the composite filaments have a fineness of 5 to 12 dtex and a relatively large fineness is selected. Therefore, they have excellent thermal stability and are applied in the backing process in the carpet manufacturing process. Thus, a carpet that can withstand the heat, its own weight, and stress that is hardly deformed can be obtained.

  Next, the present invention will be specifically described based on examples, but the present invention is not limited to only these examples. In addition, the various physical-property values in a following example and a comparative example were measured with the following method.

(1) Melt flow rate (g / 10 min): Measured at a temperature of 210 ° C. and a load of 2160 gf according to the method described in ASTM-D-1238 (E). Hereinafter, the melt flow rate is referred to as “MFR”.

(2) Melt viscosity (dPa · S): using Toyo Seiki Capillograph 1C type, temperature 190 ° C., a shear rate of 1000 sec ^-1, the melt viscosity was measured under the conditions of orifice diameter 1 mm.

(3) Melting point (° C.): Using a differential scanning calorimeter (Perkin Elma, DSC-2 type), the sample mass was measured at 5 mg and the heating rate was 10 ° C./min. The temperature giving the maximum value of was the melting point (° C.).

(4) Fineness (decitex): The fiber diameter of 50 fibers from the nonwoven web was measured with an optical microscope, and the average value obtained by correcting the density was defined as the fineness.

(5) Weight per unit area (g / m ² ): Ten sample pieces each having a sample length of 10 cm and a sample width of 5 cm were prepared from a sample in a standard state, and the mass (g) of each sample piece was weighed. The average value was converted per unit area to obtain a basis weight (g / m ² ).

(6) Dry heat shrinkage rate (%): A test piece having a width of 20 cm and a length of 20 cm was cut out, and the test piece was left to stand for 5 minutes in an atmosphere at a temperature of 140 ° C. and then cooled at room temperature. The dry heat shrinkage rates in the MD direction (machine direction) and the CD direction (direction perpendicular to the machine direction) were determined from the following mathematical formulas.
Dry heat shrinkage of nonwoven fabric _{(%) = {(A 0} -A 1) / A 0} × 100
In the above formula, A ₀ is the width or length (cm) of the initial test piece, and A ₁ is the width of the test piece when it is taken out after heating for 5 minutes in an atmosphere of 140 ° C. and cooled to room temperature. Dimension or length dimension (cm) is indicated.

Example 1
As a polylactic acid polymer, L-lactic acid / D-lactic acid = 98.6 / 1.4 mol% of L-lactic acid / D-lactic acid copolymer (hereinafter referred to as “P1”) having a melting point of 168 ° C. and MFR of 20 g / 10 min. ) Was prepared.

  On the other hand, as an aromatic polyester copolymer, a copolymer polyester having ethylene terephthalate as a repeating unit and copolymerized with isophthalic acid and having a melting point of 230 ° C. and 850 dPa · S was prepared.

  Talc in the molten polymer of P1 of the sheath component so that the core-sheath composite cross section with the copolymer polyester as the core, P1 as the sheath, and the core / sheath = 1/1 (mass ratio). After individually weighing so as to be 5 wt%, each was melted at a temperature of 245 ° C. using an individual extruder type melt extruder, and melt-spun at a single-hole discharge rate of 3.5 g / min. .

  After cooling the spun yarn with a known cooling device, it is subsequently pulled and thinned at a pulling speed of 4000 m / min into an air soccer provided below the spinneret, and opened using a known opening device and moved. It was collected and deposited as a web on a screen conveyor. The single yarn fineness of the deposited composite long fiber was 8.1 dtex.

Next, the web was passed through a hot embossing device composed of an embossing roll and a flat roll and subjected to heat treatment to obtain a long fiber nonwoven fabric having a basis weight of 120 g / m ² , which was used as a primary base fabric for tufted carpet. The conditions for hot embossing are as follows: the surface temperature of both rolls is 90 ° C., the linear pressure is 98 N / cm, the embossing roll is a textured engraving pattern, the machine direction pitch is 2.5 mm, and the pressure contact area ratio is 37%. The thing of was used. The dry heat shrinkage rate of the obtained primary base fabric for tufted carpet was 1% in the MD direction and 1% in the CD direction, and was excellent in thermal stability.

Example 2
In Example 1, a long fiber nonwoven fabric having a single yarn fineness of 11.0 dtex was obtained in the same manner as in Example 1 except that the single hole discharge rate was 4.0 g / min, and this was used as the primary for tufted carpets. A base fabric was used. The dry heat shrinkage rate of the obtained primary base fabric for tufted carpet was 1% in the MD direction and 1% in the CD direction, and was excellent in thermal stability.

Example 3
“P1” was prepared as a polylactic acid polymer.
The copolymerized polyester polymer is a copolymer obtained by copolymerizing ethylene terephthalate with butanediol, and has a melting point of 200 ° C., a temperature of 230 ° C., and a melt viscosity at a shear rate of 1000 seconds ⁻¹ of 1200 dPa. -A copolyester S was prepared.

  Using a copolymer polyester as the core and P1 as the sheath, the core / sheath portion is 1/1 (mass ratio), so that the core-sheath composite cross section is obtained. After individually weighing so as to be 5% by mass, each was melted at a temperature of 220 ° C. and melt-spun at a single-hole discharge rate of 3.5 g / min using an individual extruder-type melt extruder. . Subsequently, the air soccer ball provided below the spinneret was finely drawn at a pulling speed of 4000 m / min, opened using a known opening device, and collected and deposited as a web on a moving screen conveyor. The single yarn fineness of the deposited composite long fiber was 8.1 dtex.

Next, the web was passed through a hot embossing device composed of an embossing roll and a flat roll, and heat treated under the same hot embossing conditions as in Example 1 to obtain a long fiber nonwoven fabric having a basis weight of 120 g / m ^2. A primary base fabric for a ted carpet was used. The dry heat shrinkage ratio of the obtained primary base fabric for tufted carpet was 2% in the MD direction and 2% in the CD direction, and was excellent in thermal stability.

Comparative Example 1
In Example 1, except that the single-hole discharge rate was 1.38 g / min, the towing speed by air soccer was 4200 m / min, and the surface temperature of both rolls during the heat embossing treatment was set to 110 ° C. Produced a long fiber nonwoven fabric in the same manner as in Example 1. The single yarn fineness of the composite continuous fiber constituting the nonwoven fabric was 3.3 dtex. The obtained long fiber nonwoven fabric was in a state where the fibers were thermally fused to the inner layer of the nonwoven fabric and the fiber form could not be maintained and was crushed. Therefore, it can be imagined that the strength of the base fabric cannot be maintained through a tufting process for planting pile yarn, and it cannot be applied to a primary base fabric for tufted carpet.

Pile yarn was planted in the obtained primary base fabric for tufted carpets of Examples 1 to 3 and the long fiber nonwoven fabric of Comparative Example 1 to obtain a carpet living machine in which piles were planted on the primary base fabric. The tuft conditions were as follows. That is, a nylon crimped yarn of 1890 decitex / 108 filament was used as a pile yarn, and a tufting machine was used to measure 10 gauges / 2.54 cm, 10 stitches / 2.54 cm, and a pile height of 5 mm, and a pile yarn of 447 g / m ^2. Tufting was performed under the following conditions.

The obtained carpet raw machine was evaluated as follows, and the evaluation results are shown in Table 1.
[Tensile strength at room temperature (N / 5 cm width) and elongation (%)];
It was measured according to the tensile strength described in JIS-L-1906. That is, ten strip-shaped test pieces having a width of 5 cm and a length of 20 cm were prepared, and using a constant speed extension type tensile tester (Tensilon UT M-4-1-100 manufactured by Orientec Co., Ltd.) A tensile test was performed at a speed of 20 cm / min, measurement was performed according to JIS-L-1906, and an extension-load curve was drawn. The average value of 10 points for the maximum load value (N / 5 cm width) obtained from the obtained elongation-load curve is the tensile strength (N / 5 cm width), and the average value of 10 points for the elongation at break is It was set as elongation (%). The temperature at the time of measurement (room temperature) was 25 ° C.

[Tensile strength (N / 5 cm width) under high temperature atmosphere, elongation (%)];
Tensile strength and elongation were measured in a high temperature atmosphere of 130 ° C. in the same manner as described above. For measurement under a high temperature atmosphere, a test piece was placed at a constant spacing of 10 cm on a constant speed extension type tensile tester (Orientec Tensilon UTM-4-1-1-100) under a high temperature atmosphere of 130 ° C. After leaving for 5 minutes, a tensile test was performed to draw an extension-load curve. In the extension-load curve, the average value of 10 load values at 10% extension was obtained as the stress (N / 5 cm width) at 10% extension. It is preferable to have an appropriate stress at the time of initial extension (at the time of 10% extension) in a high-temperature atmosphere because it is difficult for thermal deformation in the backing process to occur. In the present invention, the stress at the time of 10% extension is MD direction, It is preferable that the width is 10 N / 5 cm or more in both CD directions.

[Strong retention after tufting];
The tensile strength in the CD direction (under room temperature and high temperature atmosphere) of the base fabric was measured by the method described above, and from the obtained values (CD direction tensile strength of the base fabric and CD direction tensile strength of the carpet production machine), the following formula Based on the above, the strength retention after tufting was calculated, and the following three-level evaluation was performed for strength retention after tufting. The reason why only the CD direction is evaluated is that, in the carpet manufacturing process, an external force is applied in the CD direction in the dyeing process, backing process, etc. after tufting, and the carpet is easily deformed.
Tensile strength retention after tuft (%) = (CD direction tensile strength of carpet raw machine / CD direction tensile strength of base fabric) × 100
(Evaluation of strong retention after tufting)
◎: Strength retention after tuft exceeds 120% ○: Strength retention after tuft is less than 120% to more than 100% △: Strength retention after tuft is less than 100%

The carpet green machine of Examples 1 to 3 has high strength even in a high temperature atmosphere, and has an appropriate stress when initially stretched. It can have thermal stability against the heat applied.

Claims (6)

  A polymer obtained by copolymerizing an aromatic dicarboxylic acid or aliphatic diol with alkylene terephthalate as the main repeating unit, a crystalline aromatic polyester copolymer having a melting point of 180 to 230 ° C., and a polylactic acid-based polymer The composite long fiber is composed of a long fiber nonwoven fabric in which the composite long fiber is accumulated, the single yarn fineness of the composite long fiber is 5 to 12 dtex, and the composite long fibers constituting the long fiber nonwoven fabric are A primary base fabric for tufted carpet, wherein the lactic acid polymer is thermally bonded by at least softening.   The primary base fabric for tufted carpet according to claim 1, wherein the aromatic polyester copolymer is a copolymer obtained by copolymerizing ethylene terephthalate as a main repeating unit and isophthalic acid.   The primary base fabric for tufted carpet according to claim 1, wherein the aromatic polyester copolymer is a copolymer obtained by copolymerizing butanediol with ethylene terephthalate as a main repeating unit.   The composite form of the composite long fiber is a core-sheath type in which an aromatic polyester copolymer forms a core and a polylactic acid polymer forms a sheath, or an aromatic polyester copolymer is a core. 4. A multi-leaf type in which a plurality of protruding leaf portions are formed so that a polylactic acid polymer is formed so as to surround the outer periphery of the core portion. Primary fabric for tufted carpets.   The tufted carpet according to any one of claims 1 to 4, wherein the long-fiber nonwoven fabric has at least a polylactic acid-based polymer softened by heat embossing to thermally bond the composite long fibers together. Primary fabric for use. A tufted carpet in which pile yarn is planted on the primary base fabric for tufted carpet according to any one of claims 1 to 5.