JP2000333816A - Secondary base fabric for tufted carpet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary base fabric which has excellent molding and shape retaining properties and is easily recyclable. SOLUTION: This secondary base fabric for a tufted carpet is a partially thermally press bonded long fiber nonwoven fabric, of which the long fibers are core-sheath type composite fibers formed by disposing polyethylene terephthalate(PET) in core parts and a copolyester having a melting point lower by >=15 deg.C than the melting point of the PET and >=180 deg.C in sheath parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deep drawn formability and shape retention of a tufted carpet used for a car mat.
Further, the present invention relates to a nonwoven fabric for a secondary backing of a carpet having good adhesiveness to felt.

[0002]

2. Description of the Related Art Generally, carpets for automobiles are required to have functions of forming and welding in addition to functions required of other carpets. The required functions differ depending on the parts used, and the usage conditions are wide. Therefore, severe performance is required compared with interior use. Therefore, in order to obtain moldability, a backing agent such as polyethylene or ethylene-vinyl acetate copolymer is often used as the backing agent so as to conform to the irregularities of the automobile floor. Considering heat resistance, a polyester nonwoven fabric is used.

Further, in order to improve moldability and shape retention after molding, a secondary base fabric is often attached. The secondary base fabric is bonded to a carpet in a backing process, and a felt is adhered to the secondary base fabric for press molding. In this step, in addition to the purpose of improving moldability and shape retention, adhesive performance with felt is required.

In a general car mat, only a part of a backed carpet is melt-softened in a heating furnace,
It is molded by a press molding machine. Molding method is front (front)
There are partial molding and integral molding in which the part and the rear (rear) part are individually performed, and the mold also has a complicated uneven shape. Moreover, the molded product thus obtained needs to be fitted (closely attached) to the floor (floor). In recent years, the use of a secondary backing fabric is indispensable because the backing-processed tufted carpet alone tends to break during molding when it is deep-drawn, and the needle punch alone does not maintain shape retention and deteriorates fit. It is becoming.

In general, a carpet with a secondary base fabric is manufactured by extruding a backing agent onto the back of the carpet by a ruder method, sending out a nonwoven fabric for a secondary base fabric thereon, holding the nonwoven fabric with a cooling roller, and laminating. Then, in order to attach the felt to the secondary base fabric, a method of increasing the adhesive strength between the felt and the carpet with the secondary base fabric through an adhesive application step has been adopted. However, a process of applying an adhesive is required, which complicates the manufacturing process, increases the cost, and causes an increase in weight. When used for vehicles, there is a problem that it is incompatible with the demand for weight reduction. Was.

There is also a method in which a backing agent is leached out of a gap between the secondary base cloths to have an adhesive force with felt when pressed with a cooling roller in a step of forming a carpet with a secondary base cloth. As such a secondary base fabric, a polyester woven fabric, a nonwoven fabric made of polypropylene, or the like has been used. However, in the case of the polyester woven fabric, there is a problem that the backing agent does not seep much and pills are generated at the entangled portion of the fibers. On the other hand, in the non-woven fabric of polypropylene, while carpet materials are being reused, in order to separate each member at the time of reuse, the difference in the melting point of the polypropylene non-woven fabric with the backing agent is small. The steps involved were extremely complicated and were difficult to achieve in terms of profit.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a secondary base for carpet which has excellent moldability and shape retention and can be easily reused.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, it is a long-fiber nonwoven fabric partially heat-welded, and the long fiber has a melting point of polyethylene terephthalate in the core portion and polyethylene terephthalate in the sheath portion.
A secondary fabric for tufted carpet, which is a core-sheath type composite fiber in which a copolyester having a melting point or a softening point of at least 180 ° C and a melting point or softening point of at least 180 ° C is disposed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The long fiber used in the present invention has a core portion of polyethylene terephthalate and a sheath portion of which has a melting point lower than the melting point of polyethylene terephthalate by at least 15 ° C.
It is composed of a core-in-sheath conjugate fiber in which a copolyester having a melting point or a softening point of not lower than ℃ is disposed. The copolyester is obtained by copolymerizing one or more dicarboxylic acids or derivatives thereof and one or more diols or derivatives thereof.

Examples of dicarboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, p-oxybenzoic acid,
Sodium sulfoisophthalic acid, 2,2-bis @ 4-
Aromatic dicarboxylic acids such as (β-hydroxyethoxy) phenyl} sulfonic acid, and aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid, dodecane diacid, and eicosane diacid.

On the other hand, examples of the diol component include ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, Xylylene glycol, pentaerythritol and the like can be mentioned.

The melting point or softening point of the copolyester used in the present invention must be at least 15 ° C. lower than the melting point of polyethylene terephthalate and at least 180 ° C. If the difference in melting point is less than 15 ° C, the difference in melting point from polyethylene terephthalate is too small and the polyethylene terephthalate in the core is softened or melted during hot pressing, and as a result, a nonwoven fabric excellent in flexibility and moldability cannot be obtained.
It is not economical because it is necessary to set the temperature set at the time of thermal welding to a high temperature. The reason why the melting point or the softening point is set to 180 ° C. or higher is to provide a sufficient melting point difference between the melting point of the copolyester and the polyethylene or ethylene-vinyl acetate copolymer or the like generally used as a backing agent, so that the carpet can be reused. In addition, this is to facilitate separation of each member. As a copolyester having such a melting point,
For example, isophthalic acid is added to ethylene terephthalate for 5 to 5 minutes.
Those copolymerized in the range of 25 mol% can be used. If the molar ratio of isophthalic acid is less than 5%, the difference in melting point between the copolyester and the polyethylene terephthalate is reduced, so that not only the copolyester but also the polyethylene terephthalate in the core is melted during the heat pressing treatment,
A nonwoven fabric excellent in mechanical strength and flexibility, which is the object of the present invention, cannot be obtained. On the other hand, if it exceeds 25%, there is a problem that, when the components are separated for reuse, the difference in melting point from the backing agent is small, so that separation is difficult.

The copolyester used in the present invention may be one obtained by copolymerizing the third and fourth components as long as the above-mentioned performance is satisfied.

The polyethylene terephthalate to be disposed on the core of the conjugate fiber in the present invention may be any one usually used for fibers, and specifically has an intrinsic viscosity of 0.5 to 0.5.
Those in the range of 1.20 are preferred.

These polyesters may contain optional additives such as matting agents, pigments, flame retardants, defoamers, antistatic agents, antioxidants, and ultraviolet absorbers, as long as the object of the present invention is not impaired. May be added.

The long fiber used in the present invention must be in a core-sheath type composite form in which polyethylene terephthalate is disposed in the core and copolyester is disposed in the sheath. With such a composite form, in the heat-pressing treatment, only the copolyester in the sheath is softened or melted to fuse and bond the constituent fibers, while the polyethylene terephthalate in the core is not affected by heat. Since the fiber form is retained, the nonwoven fabric has excellent mechanical properties and shape retention, and also has excellent flexibility, and thus has excellent moldability and shape retention after molding.

The structure of the core-sheath type composite form may be any structure in which the copolyester covers the entire surface of the polyethylene terephthalate. In addition to the general concentric shape sharing the center, the core component is not uniform. It may have a heart shape, an irregular cross section other than a circle, or a sea-island type.

The weight ratio of polyethylene terephthalate to copolyester constituting the composite fiber is 80/20 to 20.
/ 80, more preferably 70/30 to 4
It is preferably 0/60. If the weight ratio of polyethylene terephthalate is more than 80, the copolyester coverage will be poor, and the copolyester that bonds the fibers will be insufficient, and the nonwoven fabric will tend to have poor shape stability, and the shape retention after molding It tends to be inferior. on the other hand,
If the weight ratio of polyethylene terephthalate is less than 20, the amount of polyethylene terephthalate, which is responsible for the strength of the nonwoven fabric itself, is insufficient, and the strength of the nonwoven fabric is reduced. It is difficult, resulting in poor moldability and shape retention.

The fineness of the composite fiber is preferably 2 to 20 denier. When the fineness is less than 2 denier, the strength and rigidity of the obtained long-fiber nonwoven fabric are low, and when heat-molded,
Sufficient dimensional stability tends not to be obtained, and shape retention is also poor. On the other hand, if it exceeds 20 denier, the number of constituent fibers per unit weight is reduced, and the mechanical performance of the obtained long-fiber nonwoven fabric is impaired, or the fiber is easily detached from the hot-pressed portion, so that even when heat-formed. Sufficient shape retention cannot be obtained, and it is difficult to satisfy required performance.

In the present invention, the long-fiber nonwoven fabric is partially heat-welded, and by having this heat-welded portion, the nonwoven fabric retains its shape stability and mechanical strength and has a certain degree of rigidity. Therefore, the shape retention after the molding process is good. Areas other than the heat-welded area contain fibers that are not affected by heat and have a high degree of freedom, so they are rich in flexibility and can follow the mold even in deep drawing, and have excellent moldability. It will be. In addition, since there is an appropriate gap between the fibers, the backing agent is leached out of the gap, and the felt is satisfactorily bonded by the leached backing agent without using an adhesive. Thus, a carpet integrated as a whole can be obtained.

The area of the entire heat-pressed portion relative to the entire area of the long-fiber nonwoven fabric, that is, the press-contact area ratio is preferably 5 to 20%.
If the pressed area ratio is less than 5%, the strength and rigidity of the base fabric are insufficient, and the shape retention performance after molding tends to be poor. on the other hand,
If it exceeds 20%, the nonwoven fabric becomes too hard, and the degree of freedom of the fiber between the individual heat-pressed portions is reduced, so that the molding processability is inferior. Leaching is poor, and the adhesiveness to felt tends to be poor.

Examples of the method of performing partial heat pressure contact include a method of performing hot embossing using a hot embossing roll and a method of ultrasonic fusion treatment. Specifically, using an embossing device consisting of an embossing roll (which means an uneven roll) and a smoothing roll or an embossing device consisting of a pair of embossing rolls, the embossing roll is heated to form the convex portion on the fiber web. By pressing or softening or melting the fiber in the area that comes into contact with the convex part, the fibers are bonded to each other to form a heat-pressed part, or high-frequency ultrasonic waves are applied on a pattern roll to melt the fibers into a point shape. You only have to wear it. As a pattern of the heat-pressing portion, a scattered point, a straight line, a curved lattice, or the like may be used. In the case of a scattered point, it is not necessarily required to be a circle, but an ellipse, a rhombus, a triangle, T
Any shape such as a shape, a linear shape, a curved shape, and a well shape can be adopted.

The long-fiber nonwoven fabric used in the present invention may be prepared by a conventionally known method. That is, while collecting the long fiber group by the composite melt spinning method, the long fiber group is accumulated by being deposited on a moving collecting conveyor. Specifically, a long fiber group is spun from a normal spinneret, and after cooling the spun yarn, it is drawn and thinned by air soccer, and then spread by a normal method. Deposited as fiber web. As described above, the obtained fiber web is partially heated and pressed to fix the fibers together to form a long-fiber nonwoven fabric.

The basis weight of the secondary base fabric of the present invention is 60 g / m ^2.
The following is preferred. If the basis weight exceeds 60 g / m ² , the number of fibers is too large, the gap between the fibers is small, and the bulk becomes bulky, so that the backing agent does not sufficiently exude, and the adhesiveness to felt is insufficient. The lower limit of the basis weight is about 10 g / m ² from the viewpoint of the strength. For the above reasons, a more preferred range is 15 to 40 g / m ² .

The air permeability of the secondary fabric of the present invention is 500 cc.
/ Cm ² · sec or more. 500cc /
In the case of less than cm ² · sec, there is a tendency that the backing agent does not sufficiently exude to adhere to the felt.

Next, a method for molding using the secondary base fabric for carpet of the present invention will be described. First, pile yarn made of nylon, polypropylene, polyester, or the like is implanted in a primary base fabric made of a polyester nonwoven fabric or the like. Thereafter, a backing agent is adhered for the purpose of fixing the pile yarn and for holding the tufted carpet. At this time, the molten backing agent exits the extruder and is applied to the back surface of the tufted carpet, that is, the side opposite to the pile surface. further,
The secondary backing is adhered to cover the backing agent, and the carpet, the backing agent and the secondary backing are integrated. After that, the felt is bonded and subjected to a heat treatment, and then a desired forming process is performed.

[0027]

The present invention will be described below in detail with reference to examples. (1) Melting point (° C.) Using a differential scanning calorimeter DSC-7 manufactured by Perkin Elmer, the temperature was measured at a heating rate of 20 ° C./min. did. (2) Single yarn fineness (denier) The fiber diameter in a web state was measured with a 50-line microscope, and the average value of the fineness obtained by density correction was defined as the fineness. (3) Basis weight (g / m ² ) A 50 cm × 50 cm sample piece was taken from a standard sample.
After zero sheets were cut out and adjusted to equilibrium moisture, the weight of each sample piece was weighed, and the average value was converted to the weight per unit square meter to obtain the basis weight. (4) Tensile strength (kgf / 5 cm width) Measured according to the strip method described in JIS L 1096. That is, a sample piece having a sample length of 20 cm and a sample width of 5 cm was gripped with a constant-speed elongation type tensile tester (Tensilon RTM-500 manufactured by Toyo Baldwin Co., Ltd.) at a grip interval of 10 cm.
cm, at a tensile speed of 20 cm / min. The average value of 10 sheets in each of the MD direction and the CD direction of the base fabric was obtained. Note that the MD direction is the longitudinal direction of the base cloth, that is, the flow direction when manufacturing the base cloth, and is the machine direction (Machin direction).
e Direction), which is abbreviated MD. The CD direction is a direction perpendicular to the horizontal direction of the base cloth, that is, the vertical direction, and is also referred to as a cross direction.
Abbreviated as direction. (5) Air permeability (cc / cm ² · sec) Air permeability tester (KES-F-AP) manufactured by Kato Tech
Using 1), the airflow resistance R (Pa · sec / m) at each of the five points was measured, and the air flow rate Q (cc / cm ² · sec) was determined as Q = 12.
After calculating at 45 / R, the average value of the obtained values was defined as the air permeability.

Example 1 Polyethylene terephthalate (melting point 256) was used as the core.
° C), and a copolyester obtained by copolymerizing ethylene terephthalate with 8 mol% of isophthalic acid as a sheath (melting point: 230 ° C)
C) was prepared and melt-spun at a melting temperature of 285 ° C. using a core-shell type die at a core-sheath ratio of 60/40 (weight ratio). The filament to be ejected is drawn while being drawn by air soccer so that the spinning speed becomes 5000 m / min.
A denier core-sheath composite long fiber group was obtained. The long fiber group was spread by a fiber opening device provided at the outlet of the air soccer, and then deposited on a moving wire mesh collection conveyor to obtain a fiber web. Then, through a heat welding apparatus comprising a heated heat pressing area of 15% of the embossing roll and a smoothing roll 200 ° C., and thermocompression bonding at a linear pressure of 30 kgf / cm, for tufted carpet having a basis weight is 15 g / m ² A secondary fabric was obtained. Table 1 shows the physical properties of the obtained secondary fabric for tufted carpet.

This secondary fabric was bonded to the back of the primary fabric on which the pile yarn was planted at the same time as polyethylene resin 400 g / m ² to obtain a carpet with a secondary fabric. Further, it was bonded to felt and heat-treated, heated to 130 ° C., and put into a press equipped with a forming die to obtain a formed body. The moldability and the shape retention after molding were good.

Example 2 A secondary base fabric for tufted carpet was obtained in the same manner as in Example 1 except that melt spinning was performed at a core / sheath ratio of 70/30 (weight ratio).

Example 3 A secondary fabric for tufted carpet was obtained in the same manner as in Example 1, except that the core-sheath ratio was 30/70 (weight ratio) and melt spinning was performed.

Example 4 A secondary base fabric for tufted carpet was obtained in the same manner as in Example 1, except that the basis weight of the nonwoven fabric was changed to 50 g / m ² .

Example 5 Example 1 was repeated except that the single fiber fineness of the long fibers was 3 denier.
In the same manner as in the above, a secondary fabric for tufted carpet was obtained.

Example 6 A secondary base fabric for tufted carpet was obtained in the same manner as in Example 1, except that the single fiber fineness of the long fiber was changed to 10 denier.

Example 7 As the copolyester to be disposed in the sheath, a polyester (melting point: 200 ° C.) obtained by copolymerizing 25 mol% of adipic acid with ethylene terephthalate was used, except that the surface temperature of the embossing roll was 170 ° C. A secondary fabric for tufted carpet was obtained in the same manner as in Example 1.

Example 8 A secondary base fabric for tufted carpet was obtained in the same manner as in Example 1, except that the basis weight of the nonwoven fabric was changed to 80 g / m ² .

Comparative Example 1 A polyester (melting point: 245 ° C.) prepared by copolymerizing 4% by mole of isophthalic acid with ethylene terephthalate was prepared as a copolyester to be disposed in the sheath, and the surface temperature of the embossing roll was changed to 215 ° C. In the same manner as in Example 1, a secondary base fabric for tufted carpet was obtained.

Comparative Example 2 A polyester (melting point: 130 ° C.) obtained by copolymerizing ethylene terephthalate with 30 mol% of isophthalic acid was prepared as a copolyester to be disposed in the sheath, and the surface temperature of the embossing roll was changed to 100 ° C. In the same manner as in Example 1, a secondary base fabric for tufted carpet was obtained.

[0039]

[Table 1]

The secondary base fabrics for tufted carpets of Examples 1 to 7 have good strength and air permeability, and are excellent in moldability, shape retention and adhesiveness to felt when molded as a carpet. Met. Also, when reused, they could be easily separated.

In Example 8, the basis weight was as large as 80 g / m ² and the air permeability was low, so that the backing agent had poor leaching property and the adhesiveness to felt was insufficient, so that an adhesive was required. However, when molded as a carpet, the moldability and shape retention were good, and when it was reused, it could be easily separated.

In Comparative Example 1, the copolyester had a melting point of 24.
Since the temperature was as high as 5 ° C., the surface temperature of the embossing roll had to be increased in order to adhere the nonwoven fabric layer, so that the fiber web adhered to the embossing roll and the operability was poor.

In Comparative Example 2, the melting point of the copolyester was 13
Since the temperature was as low as 0 ° C., the fiber web adhered to the embossing roll during the heat bonding process, resulting in poor operability and a small difference in melting point from the backing agent. It was something.

[0044]

The secondary fabric for carpet according to the present invention is a long-fiber non-woven fabric partially heat-welded, and the long fiber has a core portion of polyethylene terephthalate and a sheath portion of polyethylene terephthalate having a melting point of 15%. Since it is a core-sheath type composite fiber in which a copolyester having a melting point or softening point of 180 ° C. or higher and having a melting point or softening point of 180 ° C. or higher, it has moderate strength, form stability and flexibility, Since it has excellent moldability and shape retention after molding, a carpet having good moldability can be obtained.

Further, since the secondary base fabric is composed of only the polyester-based polymer, it can be easily separated for each material when the carpet is reused.

Claims (2)

[Claims] 1. A long-fiber nonwoven fabric partially heat-welded, wherein the long fibers have a melting point of polyethylene terephthalate in a core portion and a polyethylene terephthalate in a sheath portion.
A secondary fabric for tufted carpet, which is a core-sheath type composite fiber in which a copolyester having a melting point or softening point of 180 ° C. or higher and a temperature of 180 ° C. or higher is disposed. 2. The secondary fabric for tufted carpet according to claim 1, wherein the basis weight of the long-fiber nonwoven fabric is 60 g / m ² or less and the air permeability is 500 cc / cm ² · sec or more.