Field of the Invention
[0001] The present invention relates to a base cloth for tufted carpet comprised of nonwoven
fabric made of accumulated filaments and the carpet using the same.
Background of the Invention
[0002] Nonwoven fabric made of a large number of accumulated filaments is used for base
cloth for tufted carpet. Known base cloth for tufted carpet is used as a supporting
and backing medium wherein pile yarn is embedded and tufted. The base cloth is mainly
made of nonwoven fabric of polyethylene-terephthalate.
[0003] When it becomes unnecessary the tufted carpet makes a bulky waste and is difficult
to be disposed. Because the heat quantity generated in connection with the incineration
is large when the carpet is to be disposed by incineration, the service life of the
incinerator may be shortened and toxic gas or black smoke may be generated. And when
the carpet is disposed by landfilling method there may occur a detrimental effect
on environment because of its non-biodegradable nature. When polyvinyl chloride is
used as backing layers for the carpet, dioxin may be generated when the backing layers
are incinerated.
[0004] In recent years, recycling of synthetic fiber begins to draw attention. However,
in a carpet, pile yarn is implanted onto the base cloth, and backing layers are used
in the side opposite to the pile side of this base cloth in order to prevent loss
of pile yarn. There is also a carpet of structure wherein backing layers are covered
with second base cloth. Because these materials are not made of the same raw materials,
the carpet is difficult to be recycled.
Summary of the Invention
[0005] It is an object of the present invention to solve above described problems, and to
provide a base cloth for a tufted carpet causing no environmental problem even in
the case of becoming unnecessary and to provide a tufted carpet using the same.
[0006] To achieve this object the base cloth for the tufted carpet according to the present
invention is constituted by nonwoven fabric made of filament of poly lactic acid based
polymer. The filament has a round cross-section, birefringence of 12 × 10
-3 to 30 × 10
-3 and crystallization degree of 15 to 25 percent by weight. The base cloth for the
above described tufted carpet has heat shrinkage of less than 1 percent at 120 °C
in three minutes in both directions of machine direction (MD) and cross direction
(CD).
[0007] In addition, the base cloth for the tufted carpet according to the present invention
is constituted by nonwoven fabric made of filament of poly lactic acid based polymer.
The above described filament has a non-round cross-section and crystallization degree
of 15 to 25 percent by weight. The above described base cloth for the tufted carpet
has heat shrinkage of less than 1 percent at 120 °C in three minutes in both direction
of MD and CD.
[0008] The tufted carpet according to the present invention includes the above described
base cloth. The carpet preferably has a configuration wherein the pile yarn made of
poly lactic acid based polymer is tufted on the base cloth. Preferably backing layers
made of biodegradable material is provided in the side opposite to the tufted pile
side of this base cloth.
[0009] According to the present invention, because the base cloth used for the tufted carpet
is constituted by a nonwoven fabric made of filament of poly lactic acid based polymer,
the base cloth has required biodegradability, and, as a result, does not cause environmental
problems in nature. Poly lactic acid apparently, due to its chemical structure, has
higher stiffness than polyester. By this reason, when this base cloth is tufted, it
is difficult that filaments of the base cloth are stuck directly by tufting needles
and as a result, the filament easily slips off a needle. Therefore a damage given
to fiber decreases, and mechanical strength of the tufted base cloth is maintained.
When the final product is for example a tile carpet, it maintains stiffness, and may
have an improvement in workability during the installation on the floor. When the
above described filament has crystallization degree of 15 to 25 percent by weight
and round cross-section, because this filament has birefringence of 12 × 10
-3 to 30 × 10
-3, it is apparent this filament has moderate stiffness and simultaneously the polymer
constituting the filament is oriented enough. Accordingly the final product with superior
dimensional stability and mechanical property is provided. The base cloth of the present
invention is superior in thermal stability. Therefore the base cloth has durability
to heat, without shrinking, given in the process where it is laminated or coated by
the backing layer during the backing process and where it is heated in the oven during
backing layer hardening process after the layer is attached. As a result, a carpet
with excellent dimensional stability is provided.
Brief Description of the Drawings
[0010]
FIG. 1 is a schematic view showing a cross-section of multilobed type conjugate filament
constituting the base cloth of the present invention; and
FIG. 2 is a schematic view showing a cross-section of other example of multilobed
type conjugate filament constituting the base cloth of the present invention.
Disclosure of the Invention
[0011] The base cloth for the tufted carpet of the present invention is constituted by nonwoven
fabric made of filament formed by poly lactic acid based polymer. The poly lactic
acid based polymer is superior in biodegradability and spinnability compared with
other polymers. In addition, it has higher stiffness compared with polyester or other
filament as is apparent considering the chemical structure of poly lactic acid. On
this account when this base cloth is tufted it is difficult that tufting needle directly
sticks filaments of the base cloth and as a result, the filament can slip off the
needle. Therefore the damage on the filament decreases, and mechanical strength of
the tufted base cloth is maintained. When a tile carpet, for example, is produced
as a final product, the tile carpet with enough stiffness shows an improved workability
when it is laid on the floor.
[0012] As poly lactic acid based polymer, the polymer with melting point of equal to or
higher than 100 °C selected from the following group is preferably used. The group
includes poly (D-lactic acid), poly (L-lactic acid), copolymer of D-lactic acid and
L-lactic acid, copolymer of D-lactic acid and hydroxycarboxylic acid, copolymer of
L-lactic acid and hydroxycarboxylic acid, copolymer of D-lactic acid, L-lactic acid
and hydroxycarboxylic acid. A blend of the polymers with melting point equal to or
higher than 100 °C is also preferable.
[0013] Poly (L-lactic acid) and poly (D-lactic acid) which are homopolymer of poly lactic
acid have melting point of about 180 °C. When the above described copolymer is used
as poly lactic acid based polymer, it is preferable that the copolymerizing ratio
of monomers is determined to give the melting point of the resulting copolymer of
higher than 120 °C. It is desirable for this purpose that the copolymerization mole
ratio of (D-lactic acid) /(L-lactic acid) is in the range of 100/0 to 90/10 or 10/90
to 0/100.
[0014] As hydroxycarboxylic acid in the case of copolymer of lactic acid and hydroxycarboxylic
acid, the hydroxycarboxylic acid selected from the group of glycolic acid, hydroxy
butyric acid, hydroxy valeric acid, hydroxy pentanic acid, hydroxy caproic acid, hydroxy
heptanic acid and hydroxy octanoic acid are used. It is particularly preferable to
use hydroxy caproic acid or glycolic acid in terms of cost.
[0015] In the present invention, the filament obtained from the poly lactic acid based polymer,
when it has round cross-section, necessarily has birefringence of 12 × 10
-3 to 30 × 10
-3 and crystallization degree of 15 to 25 percent by weight. "Round" here means that
cross-section is round enough where birefringence of the fiber can be measured.
[0016] Birefringence represents the degree of molecular orientation. If the birefringence
is lower than 12 × 10
-3 and the crystallization degree is lower than 15 percent by weight, residual elongation
of this filament increases because of insufficient molecular orientation and excessively
low crystalinity of the poly lactic acid consisting the filament. As a result, the
provided nonwoven fabric namely base cloth shows a tendency of having insufficient
dimensional stability and mechanical property. In addition, because the base cloth
has poor heat stability, it cannot have durability to heat given during the backing
process in the after-mentioned carpet manufacturing process, causing the base cloth
shrinking, and as a result, the carpet with excellent dimensional stability cannot
be obtained. Therefore the base cloth without above described properties is not suitable
for the base cloth of the tufted carpet.
[0017] On the other hand, if the birefringence is higher than 30 × 10
-3 and the crystallization degree is higher than 25 percent by weight, the dimensional
stability and the mechanical property of the nonwoven fabric become excellent, but
the stiffness of the filament becomes too high resulting in poor flexibility. Therefore,
the filament receives heavier damage by the tufting needle during the tufting process
and the tensile strength of the base cloth after tufting decreases. When the tufted
carpet is necessarily processed by thermal molding for example, it gives poor moldability.
[0018] When cross-sectional configuration of the filament is not round it is not possible
to measure the birefringence of the filament. In such case the limitation for only
crystallization degree is valid. The range of the crystallization degree is 15 to
25 percent by weight, the same as the above. What this range means is the same as
the above.
[0019] In the present invention, birefringence is measured using polarizing microscope with
Berek compensator and tricresylphosphate as immersion liquid.
[0020] The crystallization degree is measured by the following methods. The filament for
measuring is ground into powder and packed into an Aluminium sampling case (20 × 18
× 0.5 mm), thereby a target sample is formed. The vertically held sample is irradiated
by Cu-K α-ray from a direction perpendicular to the sample using RAD-rB type of X-ray
generator by Rigaku Corporation. As photoreceiver curved graphite monochrometor is
used. Scanning is performed in the range of 2θ = 5 to 125 degree and the crystallization
degree is obtained in the form of percent by weight by Ruland method.
[0021] It is necessary that the base cloth of the present invention has heat shrinkage of
less than 1 percent. The heat shrinkage here is the one in both MD and CD, and is
measured at 120 °C for three minutes. The reason is described below. Tufted carpet
is manufactured, as is described later, by tufting pile yarn to the base cloth and
by attaching backing layer to fix the pile yarn. When the backing layer is attached,
a backing material heated and melted is usually extruded and laminated to the base
cloth. After the lamination process the laminated carpet is introduced into oven to
dry and harden the material. If the heat shrinkage is more than 1 percent, the base
cloth cannot have durability to heat given in the backing process, giving shrinking
to the base cloth, and as a result, a carpet with excellent dimensional stability
cannot be obtained. In the case that the carpet is treated in the after-dyeing process
the carpet is treated with steam under temperature over 100 °C, and then the base
cloth shrinks resulting in the carpet with poor dimensional stability.
[0022] The structure of the filament in the nonwoven fabric providing the base cloth of
the present invention may be in the form of monocomponent structure comprised of poly
lactic acid based homopolymer or may be in the form of multicomponent structure comprised
of plurality of polymers. As the multicomponent structure, a sheath-core type, side-by-side
type, island-sea type or multilobed type structure may be preferable. In the type
of monocomponent structure, sheath-core, side-by-side or island-sea, both cases of
round and non-round cross-sections are possible. On the contrary, in the case of multilobed
type, only the non-round cross-section is possible.
[0023] Because the filament of the monocomponent structure does not contain polymer with
low melting point giving binder material, it can provide base cloth with low heat
shrinkage.
[0024] The filament of multicomponent structure is obtained from a combination of polymer
with low melting point and polymer with high melting point. The polymer with high
melting point preferably has melting point of 20 °C higher than the one of the polymer
with low melting point. And a portion of the polymer with low melting point is preferably
located on the surface of the filament. When these filaments of multicomponent structure
is used, the polymer with low melting point is softened or melted in the step of heat
treatment to manufacture the nonwoven fabric, giving thermal bonding between the filaments.
On the contrary, the polymer with high melting point maintains its filament structure
without receiving any effect by heating. As a result, the nonwoven fabric made of
the filament maintains mechanical property such as dimensional stability, tensile
strength and superior flexibility. Furthermore, the friction resistance of needle
penetrating the thermal bonding area decreases and as a result, easy tufting motion
of needle is obtained.
[0025] The weight ratio of the polymers with high melting point and low melting point in
the filament of multicomponent structure is preferably (polymer with high melting
point)/(polymer with low melting point) = 90/10 to 10/90(by weight). If this weight
ratio of the polymer with high melting point is less than 10 percent, it means the
portion of the polymer with low melting point is excessive and in some case, the melted
filament sticked to the roll used in the process of bonding with heat and pressure
to manufacture the nonwoven fabric under a certain temperature. The processability,
therefore, is damaged seriously. When the ratio of the polymer with high melting point
is less than 10 percent, the portion of the polymer with low melting point in the
area bonded with heat and pressure becomes excessive, and as a result, the mobility
of the filament is limited by harder bonding between the filaments. Then it becomes
difficult for the filament to follow needle motion and the filament is broken. And
then in some case the base cloth may not obtain the property requested as the base
cloth for carpet because of inferior mechanical strength. On the contrary, if the
ratio of the polymer with high melting point is more than 90 percent, it means the
portion of the polymer with low melting point is insufficient, and the thermal bonding
forming the nonwoven fabric cannot be enough. Therefore, the provided mechanical property
of the nonwoven fabric decreases and the advantage using the polymer with low melting
point is not performed. For this reason, the ratio of (polymer with high melting point)/(polymer
with low melting point) is more preferably 70/30 to 30/70 by weight.
[0026] It is preferable for the polymer with low melting point to have compatibility with
the polymer with high melting point. As the combination of the both polymers, for
example, a combination between copolymers of different mol ratio of D-lactic acid
and L-lactic acid and a combination between poly lactic acid as polymer with high
melting point and copolymer of lactic acid and hydroxycarboxylic acid as polymer with
low melting point are preferable.
[0027] The above described poly lactic acid based polymer may contain any additives such
as flatting agent, pigment, flame repellent, antifoaming agent, antistatic agent,
antioxidant and UV absorbant, so far as the object of the present invention is not
damaged.
[0028] When the sheath-core type multicomponent structure is used, the polymer with high
melting point is located in the core, and the polymer with low melting point which
makes the binder element to manufacture the nonwoven fabric by thermal processing
is located in the sheath. When this sheath-core structure is adopted, only the sheath
component will be soften or melted, bonding the filaments each other during the thermal
bonding process for manufacturing the nonwoven fabric. In this case, the core maintains
a form of filament. Therefore, even if the tufting needle touches the bonding between
the sheath filaments and breaks the bonding during the tufting process, the strength
of the base cloth will decrease only a little. In the case that the tufting needle
touches the filament, the sheath in the surface of the filament is damaged but the
core, in the inside of the filament, is not damaged. Thus, the filament with multicomponent
structure is less damaged than the filament with monocomponent structure and as a
result, the decrease in strength of the base cloth is smaller.
[0029] Multilobed type filament with multicomponent structure will be described in detail
in the following paragraph.
[0030] This multilobed type filament has a cross-section of a multilobed shape where the
polymer with high melting point is located in the core and the polymer with low melting
point is located in more than 2 lobe parts. More than 2 lobe parts form a plurality
of projecting part on the surface of the filament. The polymer with low melting point,
as bonding element, has wider surface area because of the above described construction.
Therefore, the nonwoven fabric can have larger number of bonded area between the filaments
of the nonwoven fabric. Accordingly when the nonwoven fabric is manufactured by bonding
with heat and pressure, enough bonding strength can be obtained without processed
under excessive pressure. As a result, the base cloth with high tensile strength and
elongation can be obtained. Because the polymer with low melting point projects on
the surface of the filament, the polymer softened or melted can flow into the void
between the filaments during the bonding with heat and pressure. As a result, the
void is filled with the polymer. This means that increase of the strength of the nonwoven
fabric is obtained not only in length and width direction but in thickness direction.
By increasing the strength in thickness direction of the nonwoven fabric configuring
the base cloth, the base cloth for the tufted carpet without peeling off between layers
during tufting process can be obtained.
[0031] The degree of the projection or the shape of the lobe part (projecting part) constituted
by the polymer with low melting point can be changed by selecting the weight ratio
of (polymer with high melting point)/(polymer with low melting point) or the ratio
of melt flow viscosity between the component polymers.
[0032] It is necessary that the number of the lobe part of the multilobed type conjugate
filament is more than 2 and preferably 3 to 10 and more preferably 3 to 6. If the
number of the lobe part is excessive, the degree of projection of the lobe part (the
projecting part) becomes small and as a result, the lobe part cannot exert its effectiveness.
[0033] FIG. 1 is a schematic view showing a cross-section of an example of multilobed type
filament constituting the base cloth of the present invention. This multicomponent
filament 1 has the polymer with high melting point 2 in its core and has two or more
lobe parts having the polymer with low melting point 3. The polymer with high melting
point 2 and the polymer with low melting point 3 each appear on the surface of the
filament 1 in turn. In this cross-section structure, the construction can be performed,
wherein the polymer with high melting point 2, which is considerably higher melting
point than temperature of bonding with heat and pressure, partially appears on the
surface of the filament 1. By using this structure the advantage is obtained, wherein
even if the temperature in the bonding with heat and pressure is raised up to about
the melting point of the polymer with low melting point 3, the surface of the thermal
pressing roll is not covered with softened or melted polymer.
[0034] FIG. 2 is a schematic view showing a cross-section of other example of multilobed
type conjugate filament constituting the base cloth of the present invention. In this
example, in FIG. 2, the projecting lobe part is formed in the shape where all the
polymer with high melting point 2 is surrounded by the polymer with low melting point
3.
[0035] Nonwoven fabric using filament is manufactured by the known method, for example,
spunbond process. In this spunbond process, filament is taken up according to melt
spinning method and the filament is then accumulated by being piled up onto moving
accumulating conveyer. In detail, the poly lactic acid based polymer is melt spun
from standard spinning nozzle. After the filament spun is cooled, it is drawn and
attenuated using an air sucker. After the filament is opened by known method, it is
accumulated as web on the moving accumulating device. The take up speed in drawing
by an air sucker is preferably, for example, 3000 to 6000 m/minute. In the case of
lower than 3000 m/minute, the molecular orientation of the poly lactic acid forming
filament is not obtained enough, therefore the tensile strength of the filament becomes
inferior. And as a result, the mechanical strength of the nonwoven fabric using the
filament becomes poor. On the other hand, in the case of higher than 6000 m/minute,
the spinnability in melt spinning will be inferior. If the filament is obtained which
does not have enough orientation of the poly lactic acid (undrawn filament) by the
speed of less than 3000 m/minute, the filament may be drawn or drawn and heated after
spinning. Thus, the filament of poly lactic acid (undrawn) may be oriented enough
and as a result, the nonwoven fabric with birefringence and crystallization degree
according to the present invention is obtained.
[0036] The example of the filament nonwoven fabric is selected from a group of the followings,
that is, the filament nonwoven fabric of monocomponent structure, the nonwoven fabric
of multicomponent structure, the nonwoven fabric blends of monocomponent filament
and multicomponent filament, and the nonwoven fabric blends of the monocomponent filament
and the monocomponent filament consisting of different polymer from that of the other.
[0037] Fineness of filament constituting the nonwoven fabric is preferably 2 to 14 dtex.
If the fineness is less than 2 dtex, the tensile strength of the nonwoven fabric becomes
low. When this nonwoven fabric needs to be processed by needle punching or by pile
tufting, the filaments may easily be cut, and even if it is blended with coarser fineness
filament, the tufted carpet obtained has a tendency to have inferior strength. On
the other hand with filament of more than 14 dtex, the number of filaments constituting
the nonwoven fabric decreases in unit weight. This means less number of bonded area
between the filaments and sometimes gives inferior mechanical property of the nonwoven
fabric obtained. In some cases, the bonded area between the filaments in the nonwoven
fabric is easily broken. Therefore, the whole nonwoven fabric becomes rough and the
flexibility of the carpet obtained may be damaged. As a result, the properties requested
cannot be obtained.
[0038] The apparent density of the base cloth of the present invention is preferably equal
to or less than 0.4 g/cm
3. When the apparent density is more than 0.4 g/cm
3, the base cloth becomes extremely coarse and the tufting needle is interrupted to
go through in the base cloth by increased friction resistance. The minimum of the
apparent density is preferably about 0.08 g/cm
3 considering the weight and thickness of the base cloth. When the apparent density
becomes too small, the thickness of the base cloth extremely increases in order to
obtain enough weight supporting the pile yarn. The thick base cloth requires more
pile yarn to obtain requested pile height and will give heavier carpet or higher cost.
The apparent density is more preferably 0.1 to 0.35 g/cm
3.
[0039] The base cloth of the present invention is preferably needle-punched nonwoven fabric
where the filaments are entangled with each other by needle punching. In the needle-punched
nonwoven fabric, because the filaments constituting nonwoven fabric are entangled
with each other not only two-dimensionally but in thickness direction, the peeling
between layers in the base cloth will not occur during the tufting process and as
a result, dimensional stability is sufficiently kept.
[0040] The preferable needle punching density, depending on the type of needle used or on
the needling depth, is generally 20 to 100 punches/cm
2. If the density is less than 20 punches/cm
2, the filaments are insufficiently entangled with each other and needle punching effect
is not obtained. On the other hand, if the density exceeds 100 punches/cm
2, the degree of entangle between the filaments becomes stronger but the filaments
are deeply damaged by the needle. As a result, the tensile strength of the filaments
intensely decreases, giving poor mechanical strength of the base cloth.
[0041] Some bonded part, in which the filaments are thermally bonded with each other, is
preferably located in the needle punched or not punched base cloth in order to increase
the stress in elongation and the tensile strength. Thermal bonding between the filaments
is performed by the method described hereinafter, that is, the method wherein the
base cloth is introduced to a heat embossing machine using a couple of embossing rolls
or a couple of embossing roll and flat roll giving thermal bonding of the filaments
at the projecting point of the embossing roll, the method wherein the base cloth is
introduced to a couple of flat roll giving thermal bonding to only the filaments on
the surface of the base cloth, and the method wherein heated air is flown to the base
cloth giving thermal bonding at the intersection point. In the above described method
the method wherein the cloth is introduced between the two rolls can control the thickness
of the base cloth.
[0042] The filaments are bonded partially with heat and pressure using embossing rolls.
In this partial bonding with heat and pressure, heat boding temperature and heat bonded
area ratio are important factors.
[0043] The temperature for bonding with heat and pressure, that is roll temperature, should
be set from (Tm-50) °C to (Tm-5) °C where Tm is the melting point of the polymer with
low melting point. If the bonding temperature of the rolls is set to be lower than
(Tm-50) °C, the polymer with low melting point is melted insufficiently causing low
bonding strength between the filaments. When the nonwoven fabric is used as the tufted
carpet base cloth, the mechanical property of the base cloth becomes poor and at the
same time the bonded area is easily broken and the layers in the base cloth peels
off each other easily by the shock of tufting action of needle. And as a result, a
base cloth with inferior property is obtained. On the other hand, if the temperature
of the rolls is set to be higher than (Tm-5) °C, the melted polymer with low melting
point sticks to an apparatus for bonding with heat and pressure, causing the resulting
operability and processability to be extremely poor. At the same time, the polymer
with high melting point is also melted or softened with the excessively high temperature
of the roll, and the base cloth obtained becomes extremely stiff and coarse. Therefore,
the friction resistance is increased when the tufting needle penetrates the base cloth.
[0044] The bonded area ratio should be 4 to 40 percent. Here the bonded area ratio means
the ratio of the bonded area to the whole area of the nonwoven fabric. If the ratio
is less than 4 percent, the bonded area is too small in the whole area of the nonwoven
fabric. In this case, the base cloth cannot obtain enough strength against tensile
stress which works to the cloth during the following process such as tufting, dyeing
and backing. On the other hand, if the ratio is higher than 40 percent, the mobility
of the filament between the bonded areas is decreased, and it becomes difficult for
the filament to follow needle motion and the filament is broken. Therefore, the tensile
strength of the base cloth in the tufted carpet is decreased.
[0045] The position in the web, which touches the projecting point of the embossing roll
during the bonding with heat and pressure, makes the bonding area. Accordingly, the
embossing roll which has 4 to 40 percent of projecting area to the whole surface area
of the roll is used. The shape of the top projecting point is equal to the shape of
the bonded are of the nonwoven fabric. The shape is not especially limited, and it
is possible to use shape of round, elliptical, rhombus, triangle, T shape, oxford
frame, rectangle, square and so forth. The area of the top projecting point is preferably
approximately 0.1 to 1.0 mm
2.
[0046] It is preferable to use linear pressure of approximately 100 to 900 N/cm in the bonding
with heat and pressure.
[0047] In the base cloth of the present invention, to improve the stress on stretching and
tensile strength, it is preferable that a binder resin is attached to the base cloth
in order to adhere the contact point between the filaments by the binder resin. The
amount of the applied binder resin (solid deposit amount) is preferably 2 to 15 percent
by weight of the total weight of the base close for the tufted carpet. If the deposit
amount of the resin is less than 2 percent by weight, the effect of using binder resin
is not performed. On the other hand, if the deposit amount is more than 15 percent
by weight, the amount of the resin between the filaments becomes excessive. Therefore,
the mobility of the filament is limited during the tufting process and the tufting
needle cannot easily penetrate the base cloth, and the flexibility of the tufted carpet
has a tendency of becoming poor. As the binder resin, the above described poly lactic
acid based polymer for the base cloth is preferably used. Or, poly vinyl alcohol,
polysaccharides that is natural polymer such as starch, proteins and chitosans may
be used. Besides, monomers such as methyl acrylate, ethyl acrylate, butyl acrylate,
methyl methacrylate, ethyl methacrylate, butyl methacrylate acrylonitrile and styrene
are used in the range that biodegradability is not damaged.
[0048] The total weight of the base close for the tufted carpet of the present invention
is set as desired and preferably is 50 to 150 g/m
2 by weight in general. If the weight is less than 50 g/m
2, the mechanical strength of the base cloth decreases. Because the total amount of
the filament in the base cloth is small, the retention power for the tufting yarn
to the base cloth is not enough, causing falling off of tufting yarn during the tufting
process. On the other hand, if the weight is more than 150 g/m
2, the total amount of the filament in the base cloth is excessive and therefore evenness
in height of the pile yarn cannot be obtained or tufting stitch becomes uneven. At
the same time, the carpet obtained has excessive performance and is not economical.
[0049] In the tufted carpet of the present invention, a biodegradable tufting yarn is implanted
by tufting method on the base cloth. The biodegradable fiber configuring the tufting
yarn is selected from the following yarn, that is, yarn made of poly lactic acid based
polymer used in the base cloth mentioned above, yarn made of aliphatic polyester,
natural fiber and regenerated fiber. Cotton wool and linen are suitable as natural
fiber, and rayon, acetate and rayon obtained by the solvent spinning method are suitable
as regenerated fiber. Cotton, wool and regenerated fiber are preferably used to obtain
excellent water absorbing property and touch. From the standpoint of recycling, the
same type of material used for the base cloth that is poly lactic acid based polymer
is preferably used and more preferably bulky textured yarn is used for tufting yarn.
[0050] In the tufted carpet of the present invention, backing layer is attached in order
to fasten the pile yarn and to reinforce the carpet in the back side of the tufted
pile yarn. As the backing material, the known bitumen, ethylene vinyl acetate resin,
polyurethane resin are preferably used. From the standpoint of biodegradability, poly
lactic acid based polymer used in the above described base cloth and aliphatic polyester
are preferably used. As the method of attaching the backing layer, for example, the
following method are used, that is, the coating or impregnating method wherein the
base cloth is coated or impregnated by the melted resin, the foam method wherein resin
solution foam is coated in the back face of the base cloth and then dried, and the
powder method wherein the power resin is melted and simultaneously coated on the surface
of the nonwoven fabric.
Examples
[0051] The examples of the present invention will be described below in detail. The present
invention, however, is not limited by the examples.
[0052] The measuring methods of each properties in the examples are as follows.
- (1) Melting point (°C) : The temperature is determined to be melting point which gives
the peak in the melting endothermic curve obtained where 5 mg of sample is measured
at temperature rising rate of 20 °C/minute using DSC-7 type of differential scanning
calorimeter made by Perkin-Elmer.
- (2) Melt Flow Rate of poly lactic acid (g/10 minutes): The extruded amount of the
melted poly lactic acid is determined to be Melt Flow Rate (hereinafter "MFR") which
is measured under the condition of load weight of 21.17N and at 210 °C according to
the method described in ASTM D1238.
- (3) MFR of polypropylene (g/10 minutes): The extruded amount of the melted polypropylene
is determined to be MFR which is measured under the condition of load weight of 21.17N
and at 230 °C according to the method described in ASTM D1238.
- (4) Spinnability: The extruded filaments are drawn by air sucker and graded into three
groups as follows.
Good: filament breakage zero/spinning end · hour
Marginal: filament breakage less than 3 times/spinning end · hour
Bad: filament breakage more than 3 times/spinning end hour
- (5) Fineness (dtex): The diameter of the 50 filaments in the web is measured using
microscope and the mean result value, adjusted by density, is determined to be fineness
(dtex).
- (6) Weight (g/m2) : Ten pieces having a length of 10 cm and width of 10 cm, cut from the sample in
standard conditions, are weighed (g) after reached moisture equilibrium. The mean
value is converted to a value per unit area giving the weight (g/m2).
- (7) Crystallization degree (percent by weight): The measuring sample of nonwoven fabric
of filament is ground into powder, packed into an aluminum sampling case (10 × 18
× 0.5 mm). The sample case is held vertically. The sample is irradiated by Cu-K α-ray
from a direction perpendicular to the sample using the RAD-rB type X-ray generator
made by Rigaku Corporation. As photo receiver, a curved graphite monochrometor is
used. Scanning is performed in the range of 2θ = 5 through 125 degree and the crystallization
degree is obtained in the form of percent by weight by the Ruland method.
- (8) Birefringence (× 10-3) : Birefringence is measured using a polarizing microscope with Berek compensator
and tricresylphosphate as immersion liquid.
- (9) NSM strength (N/5 cm width): The sample with 5 cm of width and 30 cm of length
is measured under the condition of the grip interval of 20 cm according to the strip
method described in JIS L 1096 using constant rate of extension testing machine (Tensilon
RTM-500, Toyo Baldwin Co.,). The mean value obtained from 10 samples is calculated
and the value converted by weight 100g/m2 is determined to be NSM strength. Both NSM strength in the MD (machine direction)
and CD (cross direction) are measured respectively.
- (10) Heat shrinkage of the base cloth (percent): The length of 5 samples with 20 cm
× 20 cm is measured in 3 positions in the MD and CD, respectively. The mean length
in the MD is determined to be LM0 and that in the CD is determined to be LC0. The samples are then heated under the condition of constant length in the heat air
dryer at 120 °C for 3 minutes. The length of the samples after the heat treatment
is measured in the same above described method in 3 positions in the MD and CD, respectively.
The mean value of the length in the MD is determined to be LM1 and that in the CD is determined to be LC1. The heat shrinkage of the base cloth is calculated in the following equation.
- (11) Stiffness of the base cloth (cN·cm/cm2) : Measurement is performed according to the method of measuring compressibility
of the KES-FB system. In detail 5 pieces of 20 cm × 20 cm samples are prepared for
measuring. The sample is placed on the sample table after the maximum load is set.
The sample then is compressed by the compression plate at a speed of 1 mm/50 seconds.
The compression stiffness obtained is determined to be the stiffness of the base cloth.
- (12) Strength retention after tufted: The base cloth is tufted by pile yarn. The NSM
strength (N/5 cm) of the tufted base cloth is measured according to the above described
method. The strength retention is calculated by the following equation.
The strength retention is graded into three groups as follows.
Good: The strength retention is more than 80%.
Marginal: The strength retention is equal to 55% or more and less than 80%.
Bad: The strength retention is less than 55%.
- (13) Backing processability: It is graded into three groups as follows.
Good: There are no voids between the piled fabric and the backing layer and backing
is uniformly performed.
Marginal: There are a few voids between the piled fabric and the backing layer.
Bad: There are voids between the piled fabric and the backing layer
- (14) Durability against wearing out: The pile on the fabric is pressed by a round
plain faced pressing plate with 180 cm2 of area under the pressure of 40 kPa for 5 seconds. This pressing is repeated 500
times and the degree of falling down of pile is determined as durability against wearing
out.
Good: There is no change in appearance.
Bad: The pile falls down.
- (15) Biodegradability: The measurement is performed according to ISO/14855.
Good: The biodegradability is more than 70%.
Bad: The biodegradability is less than 70%.
Example 1
[0053] Poly lactic acid copolymerized by mole ratio of (D-lactic acid) / (L-lactic acid)
= 1/99 having melting point of 170 °C, number average molecular weight of 54000 and
MFR of 50 g/10 minutes (this poly lactic acid is referred to as "PLA-1" hereinafter)
was melted at 210 °C, and the melt spinning was performed by extruding the melted
polymer using the monocomponent structure spinning nozzle. After the extruded filament
was quenched by known quenching device, the filament was drawn and made finer by an
air sucker which was set under the spinning nozzle at drafting speed of 5500 m/minute.
The filaments were spreaded open each other and deposited as filament web on a collecting
surface of a traveling conveyor. The fineness of the single filament was 3 dtex.
[0054] The filament web was partially bonded with heat and pressure using a heated embossing
roll to obtain the nonwoven fabric of filament with monocomponent structure under
the condition of; embossing pattern: point,
each bonded area: 0.6 mm
2,
embossing temperature: 115 °C and
bonded area ratio: 10 percent.
[0055] Then, the nonwoven fabric was treated by dimethyl-polysiloxane aqueous emulsion to
have 0.5 percent deposit thereof by weight of the nonwoven fabric, and moreover 12
percent by weight of binder, consisting of aqueous solution of poly lactic acid, was
given on the whole weight of the base cloth. The base cloth for tufted carpet with
weight of 100 g/m
2 was obtained.
[0056] On the other hand, poly lactic acid copolymerized by mole ratio of (D-lactic acid)
/ (L-lactic acid) = 1/99 having melting point of 170 °C, number average molecular
weight of 69000 and MFR of 30 g/10 minutes was melted at 210 °C, and the melt spinning
was performed by extruding the melted polymer using the monocomponent structure spinning
nozzle through the take up roll. The filament was drawn between the take up roll and
a drawing roll located under the take up roll. Then, the drawn filament was passed
through heated and a humidified crimping machine located under the drawing roll and
was processed by treatment of relaxing and heating to obtain poly lactic acid pile
yarn of 1430 dtex / 64 filaments.
[0057] The poly lactic acid pile yarn obtained was tufted using a tufting machine to the
base cloth of poly lactic acid for tufted carpet under the condition of gauge of 1/10,
stitch of 10/2.54 cm and loop pile height of 6 mm.
[0058] On the other hand, poly lactic acid was extruded to make film, and the film obtained
was laminated to the backside of the tufted base cloth as backing layer to obtain
tufted carpet.
[0059] The properties of the base cloth and the carpet are shown in Table 1.
Table 1
|
|
Example 1 |
Example 2 |
Example 3 |
Example 4 |
Example 5 |
Example 6 |
PLA-1 |
L/D (mole ratio) |
99/1 |
← |
← |
← |
← |
← |
MFR (g/10 minutes) ← |
50 |
← |
← |
← |
← |
← |
Melting point (°C) |
170 |
← |
← |
← |
← |
← |
PLA-2 |
L/D (mole ratio) |
- |
- |
- |
- |
- |
- |
MFR (g/10 minutes) |
- |
- |
- |
- |
- |
- |
Melting point (°C) |
- |
- |
- |
- |
- |
- |
Spinning and drafting condition |
Cross-section |
* |
← |
← |
← |
← |
← |
Weight ratio (PLA-1/PLA2) |
- |
- |
- |
- |
- |
- |
Draftimg speed (m/minute) |
5500 |
← |
5000 |
6000 |
5500 |
← |
Drafting ratio |
- |
- |
- |
- |
- |
- |
Spinnability |
Good |
Good |
Good |
Good |
Good |
Good |
Filament |
Fineness (dtex) |
3.3 |
6.6 |
← |
← |
← |
← |
Birefringence (x 10-3) |
17.9 |
17.5 |
16.4 |
18.6 |
17.5 |
← |
Crystallization degree |
18.2 |
18.3 |
17.7 |
19.2 |
18.3 |
← |
(percent by weight) |
|
|
|
|
|
|
Treatment |
Treatment method |
Embossing roll |
← |
← |
← |
← |
← |
Temperature (°C) |
115 |
← |
← |
← |
← |
← |
Binder |
Poly lactic acid |
← |
← |
← |
PVA** |
Acrylate |
Needle punching |
- |
- |
- |
- |
- |
- |
Primary base cloth |
Weight (g/m2) |
100 |
← |
← |
← |
← |
← |
NSM strength (N/5 cm width) (MD/CD) |
218/156 |
207/148 |
187/133 |
227/162 |
210/150 |
210/151 |
Heat shrinkage (percent) (MD/CD) |
0.2/0.1 |
0.3/0.1 |
0.4/02 |
0.2/0.1 |
0.3/0.1 |
0.3/0.1 |
Stiffness (cN·cm/cm2) |
0.271 |
0.302 |
0.288 |
0.310 |
0.345 |
0.306 - |
Carpet |
Strength retention |
Good |
Good |
Good |
Marginal |
Good |
Good |
Backing processability |
Good |
Good |
Good |
Good |
Good |
Good |
Durability against wearing out |
Good |
Good |
Good |
Good |
Good |
Good |
Biodegradability |
Good |
Good |
Good |
Good |
Good |
Good |
* : Monocomponent round sectional configuration
* * : Poly vinyl alcohol |
Example 2
[0060] The extruded amount of PLA-1 from the spinning nozzle was modified to obtain filaments
of single filament fineness of 6.6 dtex. Other conditions were the same as Example
1 and base cloth for tufted carpet and resulting tufted carpet were obtained.
[0061] The properties of the base cloth and the carpet are shown in Table 1.
Example 3
[0062] The extruded amount of PLA-1 from the spinning nozzle was modified and the drawing
speed by the air sucker was changed to 5000 m/minute to obtain filaments of single
filament fineness of 6.6 dtex. Other conditions were the same as Example 1 and base
cloth for tufted carpet and resulting tufted carpet were obtained.
[0063] The properties of the base cloth and the carpet are shown in Table 1.
Example 4
[0064] The extruded amount of PLA-1 from the spinning nozzle was modified and the drawing
speed by the air sucker was changed to 6000 m/minute to obtain filaments of single
filament fineness of 6.6 dtex. Other conditions were the same as Example 1 and base
cloth for tufted carpet and resulting tufted carpet were obtained.
[0065] The properties of the base cloth and the carpet are shown in Table 1.
Example 5
[0066] Instead of the binder of aqueous solution of poly lactic acid in Example 1, binder
consisting of poly vinyl alcohol aqueous solution was given to the nonwoven fabric
of monocomponent filament in Example 1 so as to contain 12 percent by weight of the
binder, and base cloth for tufted carpet was obtained. Other conditions were the same
as Example 1 and base cloth for tufted carpet and resulting tufted carpet were obtained.
[0067] The properties of the base cloth and the carpet are shown in Table 1.
Example 6
[0068] Instead of the binder of aqueous solution of poly lactic acid in Example 1, binder
consisting of acrylate aqueous solution was given to the nonwoven fabric of monocomponent
filament in Example 1 to contain 6 percent by weight of the binder, and base cloth
for tufted carpet of weight of 100 g/m
2 was obtained. Other conditions were the same as Example 1 and base cloth for tufted
carpet and resulting tufted carpet were obtained.
[0069] The properties of the base cloth and the carpet are shown in Table 1.
Example 7
[0070] The following changes were made as compared with Example 1, and tufted carpet was
obtained. The temperature of the embossing roll was set to 80 °C and nonwoven fabric
of filament was obtained by temporary bonding with heat and pressure. Then, the obtained
nonwoven fabric was passed through a needle punching machine with needle of RPD36#.
The nonwoven fabric was punched by needle density of 60 punches/cm
2 to obtain a punched web. The punched web was then bonded by heat and pressure at
temperature of 110 °C. The binder containing poly lactic acid aqueous solution was
given to the web to have 12 percent by weight of the binder to obtain base cloth for
tufted carpet.
[0071] The properties of the base cloth thus obtained and the carpet using this base cloth
are shown in Table 2.
Table 2
|
|
Example 7 |
Example 8 |
Example 9 |
Example 10 |
Example 11 |
Example 12 |
PLA-1 |
L/D (mole ratio) |
99/1 |
← |
← |
← |
← |
← |
MFR (g/10 minutes) |
50 |
← |
← |
← |
← |
← |
Melting point (°C) |
170 |
← |
← |
← |
← |
← |
PLA-2 |
L/D (mole ratio) |
- |
95/5 |
← |
← |
92/8** |
95/5 |
MFR (g/10 minutes) |
- |
50 |
← |
← |
←** |
50 |
Melting point (°C) |
- |
150 |
← |
← |
135** |
150 |
Spinning and drafting condition |
Cross-section |
* |
Sheath-core type |
← |
← |
← |
6 lobe type |
Weight ratio (PLA-1/PLA2) |
- |
70/30 |
50/50 |
30/70 |
50/50 |
← |
Drafting speed (m/minute) |
5500 |
5300 |
← |
← |
5200 |
5300 |
Drafting ratio |
- |
- |
- |
- |
- |
- |
Spinnability |
Good |
Good |
Good |
Good |
Good |
Good |
Filament |
Fineness (dtex) |
6.6 |
← |
← |
← |
← |
← |
Birefringence (x 10-3) |
17.5 |
17.1 |
16.9 |
16.4 |
15.5 |
- |
Crystallization degree |
18.3 |
18.1 |
18.0 |
17.7 |
17.0 |
18.1 |
(percent by weight) |
|
|
|
|
|
|
Treatment |
Treatment method |
Ebmbossing roll |
← |
← |
← |
← |
← |
Temperature (°C) |
110 |
105 |
← |
← |
90 |
105 |
Binder |
Poly lactic acid |
- |
- |
- |
- |
- |
Needle punching |
Punched |
- |
- |
- |
- |
- |
Primary base cloth |
Weight (g/m2) |
100 |
← |
← |
← |
← |
← |
NSM strength |
226/173 |
195/145 |
191/140 |
182/133 |
180/131 |
217/164 |
(N/5 cm width) (MD/CD) |
|
|
|
|
|
|
Heat shrinkage (percent) (MD/CD) |
0.3/0.1 |
0.4/0.3 |
0.6/0.5 |
0.8/0.6 |
1.0/1.0 |
0.3/0.2 |
Stiffness (cN·cm/cm2) |
0.294 |
0.279 |
0.285 |
0.297 |
0.389 |
0.276 |
Carpet |
Strength retention |
Good |
Good |
Good |
Good |
Marginal |
Good |
Backing processability |
Good |
Good |
Good |
Good |
Good |
Good |
Durability against wearing out |
Good |
Good |
Good |
Good |
Good |
Good |
Biodegradability |
Good |
Good |
Good |
Good |
Good |
Good |
* : Monocomponent circular round sectional configuration
* * : In Example 11, PLA-3 was used instead of PLA-2. |
Example 8
[0072] A nonwoven fabric using sheath-core type filament was manufactured. In detail, the
sheath-core type filament, wherein PLA-1 in Example 1 was located in the core and
poly lactic acid copolymerized by mole ratio of (D-lactic acid) / (L-lactic acid)
= 5/95 having melting point of 150 °C, number average molecular weight of 51500 and
MFR of 50 g/10 minutes (this poly lactic acid is referred to as "PLA-2" hereinafter)
was located in the sheath, was each melt at 210 °C. The melted polymers were extruded
through a sheath-core type nozzle by the ratio of (PLA-1 / PLA-2) = 70/30 percent
by weight and multicomponent filament was melt spun. After the extruded filament was
quenched using a known quenching device, the filament was drawn and made finer by
air sucker which was set under the spinning nozzle at drafting speed of 5300 m/minute.
Filaments were spreaded open each other and deposited as a filament web on a collecting
surface of a traveling conveyor. The fineness of the single filament was 6.6 dtex.
The filament web was partially bonded with heat and pressure using a heated embossing
roll under the condition of;
embossing pattern: point,
each bonded area: 0.6 mm
2,
embossing temperature: 105 °C and
bonded area ratio: 10 percent.
[0073] Then, the filament web was treated by dimethyl-polysiloxane aqueous emulsion to have
0.5 percent deposit thereof by weight of the filament. Thus, a nonwoven fabric consisting
of the sheath-core type filament with weight of 100 g/m
2 was obtained. This nonwoven fabric was used as base cloth for tufted carpet.
[0074] And then, the tufted carpet was obtained under the same condition as Example 1.
[0075] The properties of the base cloth and the carpet are shown in Table 2.
Example 9
[0076] The extruded amount of PLA-1 and PLA-2 from the spinning nozzle was modified and
controlled to give the ratio of (PLA-1 / PLA-2) of 50/50 percent by weight. Other
conditions were the same as Example 8 and base cloth and resulting tufted carpet were
obtained.
[0077] The properties of the base cloth and the carpet are shown in Table 2.
Example 10
[0078] The extruded amount of PLA-1 and PLA-2 from the spinning nozzle was modified and
controlled to give the ratio of (PLA-1 / PLA-2) of 30/70 percent by weight. Other
conditions were the same as Example 8 and base cloth and resulting tufted carpet were
obtained.
[0079] The properties of the base cloth and the carpet are shown in Table 2.
Example 11
[0080] Compared with the polymer of Example 8, the polymer of the sheath in the sheath-core
structure filament was changed. In detail a polymer was used as the sheath, which
was obtained by copolymerizing by mole ratio of (D-lactic acid) / (L-lactic acid)
= 8/92 having melting point of 135 °C, number average molecular weight of 49000 and
MFR of 50 g/10 minutes (this poly lactic acid is referred to as "PLA-3" hereinafter),
was melted at 210 °C. The same polymer as in Example 8 was used in the core. These
two polymers were extruded from the spinning nozzle with sheath-core structure. The
ratio of (PLA-1 / PLA-3) was adjusted to 50/50 percent by weight. The drafting speed
of an air sucker was set to 5200 m/minute and the temperature of the embossing roll
was 90 °C. Other conditions were the same as Example 8 and base cloth and resulting
tufted carpet were obtained.
[0081] The properties of the base cloth and the carpet are shown in Table 2.
Example 12
[0082] A multilobed structure was adopted as cross-section of the filament. In detail, PLA-1
used in Example 1 and PLA-2 used in Example 8 were melted at 210 °C and extruded from
the spinning nozzle to obtain the filament wherein PLA-1 was located in the core and
PLA-2 was located in the 6 lobes of sheath by the ratio of (PLA-1 / PLA-2) of 50/50
of weight ratio. As a result, the filament shown by FIG. 1 was spun as having a cross-section
of 6-lobed sheath. After the extruded filament was quenched by a known quenching device,
the filament was drawn and made finer by an air sucker which was set under the spinning
nozzle at a drafting speed of 5300 m/minute. The filaments were spreaded open each
other and deposited as a filament web on a collecting surface of a traveling conveyor.
The fineness of the single filament constituting the web was 6.6 dtex.
[0083] In the next step, the filament web was partially bonded with heat and pressure using
a heated embossing roll under the condition of;
embossing pattern: point,
each bonded area: 0.6 mm
2,
embossing temperature: 105 °C, and
bonded area ratio: 10 percent.
[0084] Then, the filament web was treated by dimethyl-polysiloxane emulsion to have 0.5
percent deposit thereof by weight of the filament, and a nonwoven fabric with a 6
lobe type filament with weight of 100 g/m
2 was obtained. This nonwoven fabric was used as base cloth. And then, tufted carpet
was obtained under the same condition as Example 8.
[0085] The properties of the base cloth and the carpet are shown in Table 2.
Example 13
[0086] PLA-1 in Example 1 and PLA-2 in Example 8 were melted at 210 °C and melt spun using
a spinning nozzle for mixed filaments with mixing ratio of (PLA-1 / PLA-2) of 70/30
percent by weight. After the extruded filaments were quenched using a known quenching
device, the filaments were drawn and made finer by an air sucker which was set under
the spinning nozzle at drafting speed of 5300 m/minute. The filaments were spreaded
open each other and deposited as a filament web on a collecting surface of a traveling
conveyor. The fineness of the filament consisting of PLA-1 and that of the filament
consisting of PLA-2 were 6.6 dtex respectively.
[0087] The filament web was partially bonded with heat and pressure using a heated embossing
roll under the condition of;
embossing pattern: point,
each bonded area: 0.6 mm
2,
embossing temperature: 105 °C, and
bonded area ratio: 10 percent.
[0088] Then, the filament web was treated by dimethyl-polysiloxane emulsion to have 0.5
percent deposit thereof by weight of the filament and a nonwoven fabric of the mixed
filaments with weight of 100 g/m
2 was obtained. Tufted carpet was obtained under the same condition as Example 8.
[0089] The properties of the base cloth and the carpet are shown in Table 3.
Table 3
|
|
Example 13 |
Example 14 |
Example 15 |
Comparative example 1 |
Comparative example 2 |
Comparative example 3 |
PLA-1 |
L/D (mole ratio) |
99/1 |
← |
← |
← |
← |
Polypropylene |
MFR (g/10 minutes) |
50 |
← |
← |
← |
← |
40 |
Melting point (°C) |
170 |
← |
← |
← |
← |
160 |
PLA-2 |
L/D (mole ratio) |
95/5 |
← |
- |
- |
- |
- |
MFR (g/10 minutes) |
50 |
← |
- |
- |
- |
- |
Melting point (°C) |
150 |
← |
- |
- |
- |
- |
Spinning and drawing condition |
Cross-section |
Mixed |
Sheath-core type |
Monocomponent round |
← |
← |
← |
Weight ratio (PLA-1/PLA2) |
70/30 |
50/50 |
- |
- |
- |
- |
Drafting speed (in/minute) |
5300 |
← |
1200 |
2300 |
7200 |
3800 |
Drafting ratio |
- |
- |
2.5 |
- |
- |
- |
Spinnability |
Good |
Good |
Good |
Good |
bad |
Good |
Filament |
Fineness (dtex) |
6.6 |
← |
← |
← |
← |
← |
Birefringence (x 10-3) |
17.0/16.6* |
16.9 |
28.3 |
10.4 |
- |
- |
Crystallization degree |
18.2/17.3* |
18.0 |
24.7 |
12.1 |
- |
- |
(percent by weight) |
|
|
|
|
|
|
Treatment |
Treatment method |
Embossing roll |
Thermal through |
Embossing roll |
← |
- |
Embossing roll |
Temperature (°C) |
105 |
155 |
125 |
115 |
- |
135 |
Binder |
- |
|
Poly lactic acid |
← |
- |
Acrylate |
Needle punching |
- |
- |
- |
- |
- |
- |
Primary base cloth |
Weight (g/m2) |
100 |
← |
← |
← |
- |
100 |
NSM strength |
192/136 |
148/140 |
275/196 |
93/88 |
- |
247/224 |
(N/5 cm width) (MD/CD) |
|
|
|
|
|
|
Heat shrinkage (percent) (MD/CD) |
0.4/0.2 |
0.1/0 |
0/0 |
38/31 |
- |
0.1/0 |
Stiffness (cN·cm/cm2) |
0.292 |
0.270 |
0.414 |
0.739 |
- |
0.211 |
Carpet |
Strength retention |
Good |
Good |
Good |
Bad |
- |
Good |
Backing processability |
Good |
Good |
Good |
Bad |
- |
Good |
Durability against wearing out |
Good |
Good |
Good |
Good |
- |
Bad |
Biodegradability |
Good |
Good |
Good |
Good |
- |
Bad |
* In Example 13, PLA-1/PLA-2 |
Example 14
[0090] The filament web obtained in Example 8 was processed by thermal through treatment
using a continuous treating machine at 155 °C. The treated web was then treated by
dimethyl-polysiloxane aqueous emulsion to have 0.5 percent deposit thereof by weight
of the filament and a nonwoven fabric of the sheath-core type filament with weight
of 100 g/m
2 was obtained. Tufted carpet was obtained under the same condition as Example 8.
[0091] The properties of the base cloth and the carpet are shown in Table 3.
Example 15
[0092] The base cloth for tufted carpet consisting of filaments was manufactured by spin
draw take up method using PLA-1 in Example 1. In detail PLA-1 was melted at 210 °C
and was melt spun by being extruded through a monocomponent structure spinning nozzle.
After the extruded filament was quenched using a known quenching device, the filament
was led to a first roll (speed of 1200 m/minute and temperature of 80 °C) located
under the nozzle. The filament was drawn between the first roll and a second roll
of 100 °C at a speed of 3000 m/ minute, and then led to a third roll (speed of 3000
m/minute and temperature of 150 °C) to be heated at constant length. The filaments
drawn at the drawing ratio of 2.5 were led to an air sucker and were spreaded open
each other and deposited as a filament web on a collecting surface of a traveling
conveyor. The fineness of the single filament was 6.6 dtex.
[0093] In the next step, the filament web was partially bonded with heat and pressure using
a heated embossing roll under the condition of;
embossing pattern: point,
each bonded area: 0.6 mm
2,
embossing temperature: 125 °C, and
bonded area ratio: 10 percent.
[0094] Then, the web was treated by dimethyl-polysiloxane emulsion to have 0.5 percent deposit
thereof by weight of the filament and a nonwoven fabric of the monocomponent filament
with weight of 100 g/m
2 was obtained. Other conditions were the same as Example 1 and base cloth and resulting
tufted carpet were obtained.
[0095] The properties of the base cloth and the carpet are shown in Table 3.
[0096] As is apparent in Table 1 to Table 3, the base cloth obtained in Example 1 to Example
15 had excellent mechanical stability and heat stability and also had excellent processability
for carpet. Especially excellent and stable productivity was performed to manufacture
the base cloth obtained in Example 8 to Example 14 consisting of the multicomponent
filaments. The filaments were adhered together firmly, nevertheless the mobility of
the filament in the base cloth was maintained. As a result, the strength retention
after tufting was excellent. The tufted carpet obtained from these base cloth had
superior biodegradability.
Example 16
[0097] Pile yarn consisting of nylon 6 of 1430 dtex / 64 filaments was tufted to the base
cloth obtained in Example 8 under the condition of gauge of 1/10, stitch 10 / 2.54
cm and loop pile height of 6 mm using tufting machine. Then, polyethylene resin was
extruded to make film. The film was laminated to the backside of the tufted base cloth
to obtain tufted carpet. In this method, the strength retention was equal to or more
than 80 percent. There could be observed no void and the backing layer was uniformly
attached to the base cloth.
[0098] Because the pile yarn and the backing layer were not biodegradable, when it came
to disposing the carpet, the component parts (the backing layer, the pile yarn and
the base cloth) could be separated. Only the base cloth with biodegradability could
be biodegraded.
Comparative example 1
[0099] The extruded amount of PLA-1 was modified and the drawing speed of the air sucker
was changed to 2300 m/minute to obtain filaments of single filament fineness of 6.6
dtex. Other conditions were the same as Example 1, and base cloth and resulting tufted
carpet were obtained.
[0100] The properties of the base cloth and the carpet are shown in Table 3.
Comparative example 2
[0101] The extruded amount of PLA-1 was modified and the drawing speed of the air sucker
was changed to 7200 m/minute to obtain filaments of single filament fineness of 6.6
dtex. Other conditions were the same as Example 1 and melt spinning was attempted.
However, there occurred a plurality of filament breakage and it was impossible to
obtain nonwoven fabric of the filament.
[0102] The processing condition and spinnability is shown in Table 3.
Comparative example 3
[0103] Polypropylene with melting point of 160 °C and MFR of 40 g/10 minutes was melted
at 230 °C and spun using the monocomponent structure spinning nozzle. After the extruded
filament was quenched using a known quenching device, the filament was drawn and made
finer by an air sucker which was set under the spinning nozzle at a drafting speed
of 3800 m/minute. The filaments were spreaded open each other and deposited as a filament
web on a collecting surface of a traveling conveyor. The fineness of this single filament
constituting the web was 6.6 dtex. The filament web was partially bonded with heat
and pressure using a heated embossing roll under the condition of;
embossing pattern: point,
each bonded area: 0.6 mm
2,
embossing temperature: 105 °C, and
bonded area ratio: 10 percent.
[0104] Then, the filament web was treated by dimethyl-polysiloxane emulsion to have 0.5
percent deposit thereof by weight of the filament, and a nonwoven fabric of the monocomponent
filament with weight of 100 g/m
2 was obtained.
[0105] In the next step, the nonwoven fabric of the monocomponent filament was dipped in
a binder of acrylate aqueous solution in Example 6 to obtain base cloth with 6 percent
by weight of acrylate binder deposit.
[0106] On the other hand, polypropylene with melting point of 160 °C and MFR of 20 g/10
minutes was melted at 230 °C, extruded through a monocomponent structure spinning
nozzle, and spun via a take up roll. The filament was drawn between the take up roll
and a drawing roll located under the take up roll. Then, the drawn filament was passed
through the heated and humidified crimping machine located under the drawing roll
and was processed by the treatment of relaxing and heating to obtain polypropylene
pile yarn of 1430 dtex /64 filaments.
[0107] The pile yarn was tufted to the base cloth consisting of polypropylene filament.
Other conditions were the same as Example 1 and tufted carpet were obtained.
[0108] The properties of the base cloth and the carpet are shown in Table 3.
[0109] As is apparent in Table 3, in comparative Example 1, the spinning speed was too low,
and birefringence and crystallization degree were less than the limited minimum value
of the present invention. The obtained nonwoven fabric had inferior mechanical property
and heat stability. At the same time, strength retention after tufted and processability
of backing were also inferior.
[0110] In comparative Example 2, spinnability at high speed spinning was poor and lots of
filament breakage occurred. Therefore, base cloth for tufted carpet could not be obtained.
[0111] The tufted carpet in comparative Example 3 did not have biodegradability and as a
result, the carpet had a problem when disposed. Moreover, due to cyclic compression,
the pile fell down causing poor appearance.