JP4269604B2 - Biodegradable ground yarn for pile knitted fabric and pile knitted fabric - Google Patents

Description

【００６８】
実施例２
上記実施例１で得られたポリ乳酸繊維を地糸（鎖糸及び挿入糸）として、１６ゲージ／ｉｎｃｈ、２６本／ｉｎｃｈで地組織を構成し、綿及びポリ乳酸の交撚糸をパイル部分として使用し、前述の方法によりマイヤー毛布を製造した。なお、染色整理工程中、パイル編布を１１０℃で縦方向に１０％収縮させた。同様に比較例１及び比較例２のポリ乳酸繊維を地糸としてマイヤー毛布を製造した。更に、ポリエチレンテレフタレート樹脂からなる表１に記載のポリエステルフィラメントを地糸として同様にマイヤー毛布を製造した。これらのマイヤー毛布の編み立て性、製造段階での加工性（センターカット性）、製造状況、及び、染色整理工程時のパイル糸の抜け落ち度合いを評価し、結果を表２に示す。
編み立て性は以下の基準で評価した。
〇：問題なし
×：糸切れが発生
【００６９】
【表２】

【００７０】
実施例１の地糸を用いたマイヤー毛布は、全ての項目において、ポリエステルフィラメントと同程度の性能を有することが示された。比較例１及び２の地糸を用いたマイヤー毛布は、パイル糸の抜け落ちがひどかったり、抜け落ちやすかったりした。また、比較例１の地糸を用いたマイヤー毛布は、編み立て性、センターカット性の悪化及び製造における不良の発生が見られた。
【００７１】
【発明の効果】
本発明のパイル編布用生分解性地糸は、生分解性を有するものであるため、これを使用したパイル編布は、廃棄された場合も自然界の微生物によって地糸が分解される。このため、パイル糸を生分解性を有する繊維を使用してパイル編布を製造すると、パイル編布全体が生分解を有するものとなるものである。また、パイル糸の抜け落ち、製造工程における糸切れ等の問題を生じることも少ないという点からみても、パイル編布用の地糸として優れた性質を有する。
本発明のパイル編布は、毛布、カーペット、マット、ソファー、こたつ敷き、こたつ掛け、ポンチョ等に用いられる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a biodegradable ground yarn for pile knitted fabric and a pile knitted fabric.
[0002]
[Prior art]
Pile knitted fabrics are widely used for blankets, carpets, and the like because they are soft to the touch and have excellent heat retention effects. A pile knitted fabric is composed of a pile portion and a ground yarn that fixes the pile portion. For example, a Mayer blanket composed of a general pile knitted fabric is knitted with a double raschel knitting machine to form a ground structure composed of the ground yarn. It is manufactured by forming a knitted fabric having pile yarns on one side by passing pile yarns between tissues and uniformly center-cutting the center part thereof. In general, the Meyer blanket uses a fiber having boiling water shrinkage as the ground yarn, and after passing the pile yarn, the pile yarn is fixed by heat-shrinking the ground yarn by heat treatment in the dyeing arrangement process. It prevents falling out. Therefore, the ground yarn does not shrink even after the heat treatment process up to the dyeing and arrangement process, and it does not cause troubles such as boiling water shrinkage to obtain a function of positively tightening the pile yarn and yarn breakage in production. Must have only tensile strength.
[0003]
A polyester filament is generally used as a ground yarn satisfying such conditions (for example, see Patent Document 1). Since the polyester filament is inserted in a tensed state at the time of knitting, there is also an advantage in manufacturing processing that the shape is stabilized in a half-contracted state after the tension is released and the center cut is easy.
[0004]
In recent years, from the standpoint of environmental protection, it has been desired to produce various fiber products using biodegradable materials that are completely decomposed by the action of microorganisms. Therefore, it is desired that the pile knitted fabric as described above is manufactured using such a biodegradable material.
[0005]
As the pile yarn in such a pile knitted fabric, natural or semi-synthetic fibers having biodegradability such as cotton, silk, wool, rayon and the like can be used. However, since the ground yarn is required to have a certain thermal shrinkage rate and tensile strength, it has been difficult to use natural fibers or semi-synthetic fibers. In addition, since normal polyester fibers do not have biodegradability, it is not preferable to use polyester filaments that do not have biodegradability as ground yarns when producing pile knitted fabrics having biodegradability. .
[0006]
As a fiber having biodegradability, a fiber made of an aliphatic polyester resin such as polylactic acid fiber has been studied, and its application to various uses has been studied. However, although studies have been made on obtaining polylactic acid fibers having low boiling water shrinkage (see, for example, Patent Document 2), sufficient studies have been made on producing polylactic acid fibers having high boiling water shrinkage. No polylactic acid fiber having both the properties of boiling water shrinkage and tensile strength has not been known.
[0007]
[Patent Document 1]
JP 2002-69808 A
[Patent Document 2]
JP 2002-145401 A
[0008]
[Problems to be solved by the invention]
In view of the above, the present invention provides a biodegradable ground yarn for a pile knitted fabric that is biodegradable and has sufficient tensile strength and high boiling water shrinkage, and a pile knitted fabric using the above ground yarn. It is intended to do.
[0009]
[Means for Solving the Problems]
  The present invention is a biodegradable ground yarn for pile knitted fabric made of polylactic acid fiber, wherein the polylactic acid fiber has a tensile strength of 3.5 cN / dT (centinewton / dtex) or more and a boiling water shrinkage rate. 5-30%The relative viscosity is 2.5 to 3.8, the amount of monomer is 0.5% by mass or less, the ratio of the L body is 90% or more, and the ground yarn constituting the ground structure of the pile knitted fabric Used at least for chain yarnA biodegradable ground yarn for pile knitted fabrics.
[0010]
  The present invention is a pile knitted fabric comprising a ground yarn and a pile yarn,At least the chain yarnThe pile knitted fabric is a biodegradable ground yarn for pile knitted fabric.
The pile yarn is preferably made of cotton, silk, wool, rayon, polylactic acid fiber, or a mixture of two or more thereof.
Moreover, it is preferable that the pile knitted fabric is obtained by shrinking the pile knitted fabric in the longitudinal direction by 10 to 15%.
The present invention is described in detail below.
[0011]
The biodegradable ground yarn for pile knitted fabric of the present invention is a polylactic acid fiber suitably used as the ground yarn for pile knitted fabric used for blankets and carpets, etc., and has a specific tensile strength and boiling water shrinkage. It is. The biodegradable ground yarn for pile knitted fabric of the present invention may be a multifilament or a fiber composed of short fibers as long as it has the above-mentioned specific tensile strength and boiling water shrinkage ratio. A multifilament is preferable from the viewpoint of obtaining excellent boiling water shrinkage.
[0012]
The biodegradable ground yarn for pile knitted fabric of the present invention is made of polylactic acid fiber. The polylactic acid is an aliphatic polyester resin obtained by polymerizing lactic acid, and various uses are being studied as a biodegradable resin.
The polylactic acid fiber can be produced by spinning a polylactic acid resin by a spinning method such as melt spinning or solution spinning. Among these, it is preferable to produce by a spinning and drawing process because it is easy to adjust physical properties such as boiling water shrinkage and the environmental load in production is small.
[0013]
The melt spinning is a method in which a polylactic acid resin is heated and melted to a melting point or higher, and discharged and cooled in the air from a spinneret having minute holes to form fibers. The fiber discharged and cooled from the base is then wound up. When the polylactic acid fiber is a multifilament, the winding method is not particularly limited, for example, a method called conventional spinning, a winding speed of about 2000 m / min or less, a winding called POY (Partial Oriented Yarn) method. A method with a take-up speed of about 5500 m / min or less, a method called a HOY (Highly Oriented Yarn) method with a take-up speed of about 5500 m / min or more, or an SPD (Spin Draw) method in which stretching is performed immediately in the same apparatus after spinning. Can be mentioned.
[0014]
When the polylactic acid fiber is a short fiber, it is usually wound at a lower winding speed than the multifilament in order to push out from a large number of nozzles as compared with the multifilament. When the polylactic acid fiber is a short fiber, spinning is usually performed at a winding speed of 2000 m / min or less. In particular, it is preferably performed at around 1000 m / min.
[0015]
The method for producing the polylactic acid resin for forming the polylactic acid fiber is not particularly limited, and examples thereof include a polymerization method using lactic acid or lactide which is a dimer of lactic acid. The lactic acid can be produced by fermenting glucose to lactic acid bacteria. At the time of production by the above method, L-form, D-form and racemic form can be prepared by selecting the strain. The said glucose can be manufactured by fermenting polysaccharide, and it is not specifically limited as said polysaccharide, For example, corn starch etc. can be used. In addition to the above production method, disaccharides such as sucrose can be produced by chemical treatment.
[0016]
  The polylactic acid isThe ratio of L-form is 90% or moreUse the L-typeIs a thing. This is because the L-form has higher thermal stability. 90% or more of the polylactic acid component is L-formR95% or more is more preferably L-form, and 98% or more is most preferably L-form.
[0017]
The polylactic acid fiber may have a component other than polylactic acid as a copolymer component or other polymer. The polylactic acid fiber preferably has a polylactic acid content of 80% by mass or more. The content of the polylactic acid is more preferably 90% by mass or more, and further preferably 95% by mass or more. The component other than polylactic acid contained in the polylactic acid fiber is not particularly limited as long as it is a biodegradable component, and examples thereof include hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, hydroxycaproic acid, and the like. Hydroxyl salts, ethylene glycol, propylene glycol, butanediol, neobentyl glycol, glycerin, pentaerythritol, polyethylene glycol and other compounds containing multiple hydroxyl groups in the molecule or derivatives thereof, adipic acid, sebacic acid, fumaric acid An aliphatic polycarboxylic acid such as
[0018]
The polylactic acid resin forming the polylactic acid fiber preferably has a linear polymer structure. That is, it is preferable to have almost no branched structure. In order to improve the melt viscosity and the degree of polymerization, a small amount of a branching agent is added when polymerizing a polylactic acid resin, but the branched structure of the polylactic acid resin is a normal synthetic fiber such as a polyester filament. It has been confirmed that it greatly affects the spinning operability. That is, the polylactic acid resin having almost no branched structure has very good operability during spinning and has a high tensile strength. In order to eliminate the branched structure, it is not necessary to use a raw material monomer that generates a branched structure in a raw material of a polymer such as a trivalent or higher alcohol or carboxylic acid. Even when components having these structures are used for other reasons, it is preferable to keep the amount to the minimum necessary amount that does not affect the spinning operability.
[0019]
The polylactic acid preferably has a TG (5%), which is a 5% decrease in polymer mass, of 300 ° C. or higher. The higher the temperature of TG (5%), the more the thermal deterioration in fiber production and fiber processing can be prevented.
[0020]
The polylactic acid preferably has a mass average molecular weight Mw within a range of a lower limit of 120,000 and an upper limit of 220,000, and a number average molecular weight Mn of preferably within a range of a lower limit of 60000 and an upper limit of 110000. By being within the above range, excellent spinnability and sufficient tensile strength can be obtained.
[0021]
The polylactic acid preferably has a Sn (tin) content in the polymer of 30 ppm or less, more preferably 20 ppm or less. An Sn-based catalyst is used as a polymerization catalyst for polylactic acid, but if it is 30 ppm or less, there is no risk of depolymerization during spinning, and there is no increase in the base filtration pressure, so that the spinning operability is remarkably improved. It is. The method for reducing the Sn (tin) content is not particularly limited, and examples thereof include a method for reducing the amount used during polymerization and a method for washing the chip with an appropriate liquid.
[0022]
Further, the polylactic acid may be a matting agent such as titanium dioxide, a stabilizer such as phosphoric acid, an ultraviolet absorber such as a hydroxybenzophenone derivative, a crystallization nucleating agent such as talc, a lubricant such as aerosil, if necessary. It may contain an antioxidant such as a hindered phenol derivative, a flame retardant, an antistatic agent, a pigment, a fluorescent brightener, an infrared absorber, an antifoaming agent, and the like.
[0023]
  The polylactic acid fiber has a relative viscosity (ηrel) in the fiber state of a lower limit of 2.5 and an upper limit of 3.8.Is a thing. If it is in the said range, the fiber which has sufficient tensile strength can be obtained. The lower limit is more preferably 2.7, and the upper limit is more preferably 3.1.
[0024]
In order to obtain a polylactic acid fiber having the above relative viscosity, it is preferable to obtain a polylactic acid fiber by using a polylactic acid resin having a relative viscosity in the range of a lower limit of 2.7 and an upper limit of 4.0. This is because the relative viscosity is slightly decreased by melting the polylactic acid resin to produce the fiber. Further, since the relative viscosity is 4.0 or less, it is not necessary to raise the spinning temperature so much, so that the thermal degradation during spinning is small and polylactic acid tends to flow, which is preferable.
[0025]
The polylactic acid resin preferably has a reduction rate of relative viscosity in spinning of 7% or less. By adjusting to the above range, the polymer is hardly decomposed during spinning, and there is no occurrence of yarn breakage during spinning. Therefore, the spinnability is good and the tensile strength in the stretching process can be increased.
[0026]
  Residual monomers may be present in the polylactic acid fiber. In the present specification, the residual monomer means a component having a molecular weight of 1000 or less calculated by GPC analysis. The residual monomer is present in the polylactic acid within a range of 0.5% by mass or less.Is a thing. If the residual monomer exceeds 0.5% by mass, the heat resistance of the fiber is lowered, and there is a risk of problems such as a decrease in tensile strength.Is. The upper limit is more preferably 0.3% by mass. The lower limit is preferably 0.01% by mass.
[0027]
The method for reducing the residual monomer in the polylactic acid fiber is not particularly limited. For example, a method of removing the unreacted monomer by vacuum suction of the reaction vessel immediately before the completion of the polymerization reaction of the raw material polylactic acid, Examples thereof include a method of washing a lactic acid chip with an appropriate liquid, a method of performing solid phase polymerization, and the like.
[0028]
The biodegradable ground yarn for pile knitted fabric of the present invention has a tensile strength of 3.5 cN / dT or more. By setting the tensile strength to 3.5 cN / dT or more, yarn breakage does not occur in the processing process of the pile knitted fabric, and generation of defective products can be minimized. Also, the obtained pile knitted fabric is less likely to cause problems such as pile yarn slippage. The tensile strength is more preferably 3.9 cN / dT or more, and still more preferably 4.4 cN / dT or more. The upper limit of the tensile strength is not particularly limited, but it is usually difficult to produce a product having a tensile strength of 5.3 cN / dT or higher.
[0029]
The tensile strength is obtained by conducting a tensile test of the fiber with a tensile tester and converting the force applied to the fiber at the time of breaking as the strength per unit thickness of the fiber. As the tensile tester, a Shimadzu tensile tester (RTM-100) is used, and a measurement value obtained by performing a test length of 20 cm and a speed of 20 cm / min is used.
[0030]
The biodegradable ground yarn for pile knitted fabric of the present invention has a boiling water shrinkage within a range of 5% lower limit and 30% upper limit. When the boiling water shrinkage of the biodegradable ground yarn for pile knitted fabric is less than 5%, the shrinkage of the ground yarn becomes insufficient and the pile yarn is not sufficiently fixed. If it exceeds 30%, the shrinkage is sufficient, but it becomes difficult to set processing conditions, and it is difficult to produce a uniform product. The lower limit is preferably 8%, and more preferably 10%. The upper limit is preferably 25%, more preferably 20%.
[0031]
The boiling water shrinkage rate is a value indicating the shrinkage rate of the fiber when immersed in boiling water. The sample having an initial value of 50 cm is immersed in boiling water for 15 minutes with an initial load of 200 mg, and then air-dried for 5 minutes. It is obtained by the formula.
Boiling water shrinkage rate (%) = {(initial sample length−sample length after shrinkage) / initial sample length} × 100
[0032]
The biodegradable ground yarn for pile knitted fabric of the present invention has these physical properties within the intended range by adjusting the processing conditions of the resin and the fiber forming the polylactic acid fiber and the manufacturing process. Can do.
[0033]
Polylactic acid generally tends to have better tensile strength and lower boiling water shrinkage as it is closer to an L-form homopolymer. Therefore, when the ratio of L-form is large, the heat setting condition in the production process of the fiber in the production process is high by setting the temperature lower than that of polyester, for example, 110 ° C. or more and less than 150 ° C. in the case of multifilament. Shrinkage can be obtained, and when the proportion of L-form is small, by setting the stretching step and heat set temperature higher in the manufacturing process than in the former, the oriented crystal is advanced and high tensile strength is achieved. Can get to.
[0034]
In order to obtain the biodegradable ground yarn for pile knitted fabric according to the present invention in view of easy control of the production process and easy to obtain high tensile strength, polylactic acid having a large L-form content is used. Thus, it is preferable to obtain the biodegradable ground yarn for pile knitted fabric of the present invention. The polylactic acid is preferably 90% or more in L form. Moreover, it is preferable not to contain copolymerization components other than D-lactic acid. When the ratio of L-lactic acid is lowered, an amorphous structure is formed, and oriented crystals do not advance in the spinning / drawing process, so that the physical properties of the obtained fiber may be lowered.
[0035]
As the spinning conditions for spinning polylactic acid fiber multifilaments with 90% or more of the L-lactic acid, the yarn is extruded into the air from a spinning nozzle, and then subjected to heat treatment at 95 to 125 ° C. while being wound and stretched. Next, the method of heat setting at 110 ° C. or higher and lower than 150 ° C. is most preferable. When heat setting is performed at a temperature lower than 110 ° C., the boiling water shrinkage rate becomes too high, and excessive shrinkage occurs during blanket production, making it difficult to control the production conditions and possibly causing insufficient tensile strength. There is. When heat setting is performed at a temperature of 150 ° C. or higher, the tensile strength is improved, but the boiling water shrinkage is lowered, and it may be difficult to use as a ground yarn for a pile knitted fabric. The lower limit of the heat set temperature is more preferably 120 ° C.
[0036]
When the biodegradable ground yarn for pile knitted fabric of the present invention is a multifilament, the total fineness is preferably in the range of a lower limit of 110 dT and an upper limit of 560 dT. If it is less than 110 dT, the strength may be insufficient and a single yarn breakage may occur. If it exceeds 560 dT, there is a possibility that a problem that knitting is difficult may occur.
[0037]
In the multifilament, the fineness of the single yarn constituting the multifilament is preferably in the range of a lower limit of 2 dT and an upper limit of 8 dT. If the thickness of the single yarn is less than 2 dT, the yarn may be broken. If the thickness of the single yarn exceeds 8 dT, the texture becomes hard and the texture of the pile knitted fabric may be deteriorated. .
[0038]
The cross-sectional shape of the biodegradable ground yarn for pile knitted fabric of the present invention is not particularly limited, and is round, triangular, L, T, Y, W, Yaba, flat, dog It may be a polygonal shape such as a bone shape, a multileaf shape, a hollow shape or an irregular shape.
[0039]
The biodegradable ground yarn for pile knitted fabric may be a polylactic acid based composite fiber. The polylactic acid-based composite fiber is not particularly limited, and examples thereof include a core-sheath type and a side-by-side type. The polylactic acid-based composite fiber is preferably in a form in which a component having the lowest melting point (for example, 130 ° C.) is exposed on a part of the fiber surface. Use of the above-mentioned polylactic acid-based composite fiber is preferable because the properties as a heat-fusible binder can be suitably imparted to the polylactic acid fiber. The polylactic acid fiber in the ground yarn may be a combination of ordinary polylactic acid fiber and polylactic acid-based composite fiber.
[0040]
The method for producing the polylactic acid-based composite fiber is not particularly limited, and examples thereof include a method of simultaneously eluting and spinning two or more kinds of polymers from a die having a specific shape.
[0041]
The pile-knitted biodegradable ground yarn may be a processed yarn subjected to false twisting. The false twisting processing method is not particularly limited, and examples thereof include a pin type, a friction type, a nip belt type, and an air false twist type. It may be a stretched false twist of POY.
[0042]
  The present invention is also a pile knitted fabric obtained using the biodegradable ground yarn for a pile knitted fabric. In the present specification, a pile knitted fabric refers to a knitted fabric having napped fibers made of pile yarn. In addition, the ground yarn constituting the ground structure of the pile knitted fabric includes a chain yarn (longitudinal direction) and an insertion yarn (lateral direction).IIt works to tighten the thread. In the present invention, it is particularly necessary to use polylactic acid fiber for the chain yarn. The insertion yarn may be a polylactic acid fiber or another biodegradable fiber.
[0043]
The production method of the pile knitted fabric of the present invention is not particularly limited as long as it is a general production method. For example, if it is a Mayer blanket, the yarn is knitted with a double raschel knitting machine, and then center-cut and the dyeing arrangement step is performed. After carrying out, combing and shearing, there can be mentioned a method of pasting two pieces with the back side of the fabric facing inward, and a method of raising the back side after performing shirring in the case of a New Meyer blanket. These blankets may optionally be polished after combing or raising.
[0044]
Although the kind of pile yarn in the pile knitted fabric of this invention is not specifically limited, It is preferable to consist of a fiber which has biodegradability. As the fiber having biodegradability suitable for use in the pile yarn, cotton, silk, wool, rayon, polylactic acid fiber, or a mixture thereof is more preferable. These fibers are preferable in that they are excellent in texture, touch, heat retaining performance and the like as a pile knitted fabric material.
[0045]
The pile yarn of the present invention is not particularly limited, and examples thereof include multifilament, spun yarn, composite spun yarn and the like, and spun yarn is particularly preferable. The spun yarn may be a spun yarn composed of the above-mentioned various fibers alone or a mixed spun yarn composed of two or more kinds of fibers. Among these, a blended yarn of polylactic acid short fibers and natural fibers is preferable, and a blended yarn of polylactic acid fibers and cotton is most preferable. A blended yarn of polylactic acid and cotton is most preferable in that it has an excellent texture and hardly causes problems such as yarn loss. Moreover, when using a multifilament, it is preferable to use the false twisted yarn consisting of a polylactic acid fiber.
[0046]
The blending method of the polylactic acid fiber and the natural fiber is not particularly limited, and for example, a blending method described in JP 2000-80531 A can be used.
[0047]
Examples of the natural fiber blended with the polylactic acid fiber in the blended yarn include cotton fiber, silk fiber for silk spinning, and wool fiber. Each of the above-mentioned cotton, silk, and wool fibers is made of staple fibers having inherent fineness and fiber length. The polylactic acid short fiber is produced by a general method and has a necessary fiber length.
[0048]
It is preferable that the polylactic acid short fiber used for the blended yarn is close to the natural fiber for blending the fineness and the fiber length in order to increase the uniformity of the obtained blended yarn. For example, when blended with cotton fibers, it is preferable to use polylactic acid short fibers having a fineness of 1.1 to 2.2 dT and a fiber length of 30 to 60 mm. Similarly, in the case of eyelash spinning using both wool and polylactic acid fiber, the fineness of the polylactic acid fiber is preferably 3.3 to 8.0 dT, and the fiber length is preferably 60 to 120 mm. The fineness of the lactic acid fiber is preferably 3.3 to 8.0 dT, and the fiber length is preferably 60 to 150 mm.
[0049]
The polylactic acid fiber is not limited to a straight fiber cut to a predetermined length after spinning and drawing, and after crimping by a stuffing method, an indentation heating gear method, a high-speed air injection indentation method, or the like, 30 to 150 mm Cut fibers cut to length can also be used.
[0050]
In the production of the blended yarn, the polylactic acid fiber and the natural fiber are mixed in a series of spinning processes. As the blending method, the raw cotton method that blends in the raw cotton state before the sooting process, the sliver method that blends both fibers in individual wadding machines and then blends them in the sliver state, and the individual roving yarns for both fibers, respectively. Then, a roving method in which both are combined with a spinning machine can be considered. In cotton spinning and eyelash spinning, it is preferable to mix in a sliver state from the point of uniformity, and in the case of wool spinning, it is preferable to mix in a raw hair state.
[0051]
The blended yarn preferably contains polylactic acid fibers in a range of 20% by mass for the lower limit and 80% by mass for the upper limit. If any blended amount is less than 20% (mass ratio), the properties of one of the fibers may be lost.
[0052]
The blended yarn is passed through any of the known cotton yarn spinning process (1 inch spinning), eyelash spinning step (2,2.5, 3 inch spinning), wool spinning spinning process, silk spinning spinning process, etc. Both fibers are mixed at a predetermined portion in the inside, and are spun into a spun yarn to be sent out from the spinning machine. The spun yarn can be used as the pile yarn of the present invention as a single yarn or twisted.
[0053]
The composite spun yarn is also described in JP-A No. 2000-80531. In the spinning process, the composite spun yarn is (1) supplied to the drafting part of the spinning device, and the raw natural fiber yarn just after exiting the front roller is left in the opened state, and the drafted part is then placed on it. Core yarn type obtained by superimposing and twisting polylactic acid fiber filament yarns that have passed only through the front roller without being supplied. (2) Natural yarn immediately after leaving the front roller after being supplied to the drafting part of the spinning device. A silofil type obtained by placing a polylactic acid fiber filament yarn in the center with a coarse yarn of fiber arranged on both sides, not supplied to the draft part, and passing through only the front roller, and (3) Examples thereof include a covering type and a twisted yarn type obtained by twisting natural fiber spun yarn and polylactic acid fiber filament. Note that the above “Silofil” is a registered trademark of Wool Development International Limited.
[0054]
The multifilament as the pile yarn is not particularly limited, and is obtained by similarly spinning the same polylactic acid as the biodegradable ground yarn for pile knitted fabric, and has a boiling water shrinkage of 15% or less. It is preferable to use a filament. Moreover, it is preferable to use the processed yarn which gave the false twist process on the same conditions as the said biodegradable ground yarn for pile knitted fabrics from the point of a texture.
[0055]
The manufacturing method of the pile knitted fabric of this invention is not specifically limited, It can manufacture according to the manufacturing method of a normal pile knitted fabric using the said fiber. Moreover, the pile knitted fabric of this invention can be used for a blanket, a carpet, etc., for example. In addition, the shrinkage rate in the manufacturing process of the pile knitted fabric of the present invention is preferably 10 to 15% in the longitudinal direction, which is the chain yarn direction, from the viewpoint of the tightness and texture of the pile yarn.
[0056]
The biodegradable ground yarn for pile knitted fabric made of the polylactic acid fiber of the present invention is a fiber having biodegradability, but has the same boiling water shrinkage as a polyester filament that has been conventionally used as a ground yarn for pile blankets. It has physical properties such as tensile strength. In addition, the pile knitted fabric using the biodegradable material for the ground yarn and the pile portion of the present invention is itself biodegradable and is similar to a pile knitted fabric using a conventional polyester filament as the ground yarn. The pile yarn is less likely to fall off.
[0057]
【Example】
Examples The present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
Polylactic acid fibers having various physical properties as shown in Table 1 were produced by the following polymerization and spinning processes. For comparison, physical properties of the polyester filament are shown.
[0058]
Example 1
(Polymer polymerization)
A polylactic acid was polymerized by a conventional method using a monomer composition composed of 98.6% L-lactide and 1.4% D-lactide using tin octylate as a polymerization catalyst.
[0059]
(spinning)
The obtained polymer was extruded into the air from a spinning nozzle having a pore diameter of 0.25 mm, wound up at 3500 m / min, then stretched twice at 95 ° C., and heat-set at 145 ° C. to obtain polylactic acid fibers. . The obtained polylactic acid fiber was 167 dT / 48 f.
[0060]
Comparative Example 1
A polylactic acid fiber was obtained in the same manner except that the polylactic acid polymer was changed.
[0061]
Comparative Example 2
All other conditions were the same, and a polylactic acid fiber subjected to heat setting twice was obtained.
[0062]
The resulting polylactic acid fiber was evaluated for tensile strength, boiling water shrinkage, and the like by the following methods.
<Measurement of tensile strength>
Using a Shimadzu tensile tester (RTM-100), a tensile test was performed at a sample length of 20 cm and a speed of 20 cm / min. The breaking strength was taken as the tensile strength and the breaking elongation was taken as the tensile elongation.
[0063]
<Boiling water shrinkage>
An initial load of 200 mg was applied to a sample having an initial value of 50 cm, immersed in boiling water for 15 minutes, air-dried for 5 minutes, and then the boiling water shrinkage was determined by the following equation.
Boiling water shrinkage rate (%) = {(initial sample length−sample length after shrinkage) / initial sample length} × 100
[0064]
<Relative viscosity (ηrel)>
The sample was dissolved in a mixed solvent of phenol / tetrachloroethane = 60/40 (mass ratio) to a concentration of 1 g / dl, and the relative viscosity was measured at 20 ° C. using an Ubbelohde viscometer.
[0065]
<Amount of monomer>
The sample was dissolved in chloroform so as to have a concentration of 10 mg / mL, and then GPC analysis was performed by using HLC8120GPC manufactured by Tosoh, using chloroform as a solvent, and Mw and Mn were measured. The detector was RI, and polystyrene was used as a molecular weight standard. From the measurement of the molecular weight distribution, the proportion of components having a molecular weight of 1000 or less was determined, and the amount of monomer in the polymer was calculated.
[0066]
<Measurement of L body>
The resin was hydrolyzed, and the ratio of L-form was determined using high performance liquid chromatography (HPLC: LC10AD type, manufactured by Shimadzu Corporation) using methanolic sodium hydroxide solution 1.0N as a solvent.
[0067]
[Table 1]

[0068]
Example 2
Using the polylactic acid fiber obtained in Example 1 as the ground yarn (chain yarn and insertion yarn), the ground structure is composed of 16 gauge / inch, 26 pieces / inch, and cotton and polylactic acid intertwisted yarn as the pile portion A Meyer blanket was prepared using the method described above. During the dyeing and arranging step, the pile knitted fabric was shrunk 10% in the longitudinal direction at 110 ° C. Similarly, a Meyer blanket was produced using the polylactic acid fibers of Comparative Examples 1 and 2 as the ground yarn. Further, a Mayer blanket was produced in the same manner using the polyester filaments shown in Table 1 made of polyethylene terephthalate resin as the ground yarn. The knitting properties of these Meyer blankets, processability at the manufacturing stage (center cut property), manufacturing conditions, and the degree of pile yarn falling off during the dyeing arrangement process were evaluated, and the results are shown in Table 2.
The knitting property was evaluated according to the following criteria.
Y: No problem
×: Yarn breakage
[0069]
[Table 2]

[0070]
The Meyer blanket using the ground yarn of Example 1 was shown to have the same performance as the polyester filament in all items. The Meyer blanket using the ground yarns of Comparative Examples 1 and 2 had a severe pile yarn dropout or was easy to fall off. In addition, the Meyer blanket using the ground yarn of Comparative Example 1 showed deterioration in knitting property, center cut property, and occurrence of defects in production.
[0071]
【The invention's effect】
Since the biodegradable ground yarn for pile knitted fabric of the present invention has biodegradability, the pile knitted fabric using the same is decomposed by natural microorganisms even when discarded. For this reason, if a pile knitted fabric is manufactured using the fiber which has biodegradability for a pile yarn, the whole pile knitted fabric will have biodegradation. Further, from the viewpoint that there are few problems such as falling off of pile yarns and yarn breakage in the production process, it has excellent properties as a ground yarn for pile knitted fabrics.
The pile knitted fabric of the present invention is used for blankets, carpets, mats, sofas, kotatsu mats, kotatsu racks, ponchos and the like.

Claims (4)

A biodegradable ground yarn for pile knitted fabric made of polylactic acid fiber,
The polylactic acid fiber is a tensile strength of 3.5 cN / dT (centiNewtons / dtex) or higher, boiling water shrinkage rate Ri 5-30% der, relative viscosity of 2.5 to 3.8, monomer the amount is not more than 0.5 mass%, the proportion of L-isomer is 90% or more, and pile knitting, wherein Rukoto used in at least the chain yarns of the ground yarns constituting the foundation structure of the pile knitted fabric Biodegradable ground yarn for fabric. A pile knitted fabric made of ground yarn and pile yarn,
The pile knitted fabric characterized in that at least chain yarn of the ground yarn is the biodegradable ground yarn for pile knitted fabric according to claim 1. The pile knitted fabric according to claim 2, wherein the pile yarn is made of cotton, silk, wool, rayon, polylactic acid fiber, or a mixture of two or more thereof. The pile knitted fabric according to claim 2 or 3, wherein the pile knitted fabric is contracted by 10 to 15% in the longitudinal direction.