JPS6392750A - Carpet base cloth and its production - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Industrial Field of Application) The present invention relates to the construction of a carpet base fabric woven with flat yarn drawn tape and to a method for manufacturing the base fabric.

(Prior Art) As a tufted carpet base fabric, one woven with flat yarns made of polypropylene resin is known. Polypropylene resin is sensitive to heat and lacks dimensional stability, so there is no problem with it as a base fabric for general carpets, but in the case of tile carpets, latex is applied to the back side of the carpet, so the coating process is difficult. Traditionally, base fabrics for tile carpets have mostly been made from non-woven fabrics made of polyester resin, as it is not possible to meet the demands for high dimensional accuracy and elegance in the heat of time. It is.

(Problems to be Solved by the Invention) However, since nonwoven fabrics made of polyester resin are extremely expensive, there is a need for base fabrics that are inexpensive, have excellent heat resistance, and have high dimensional stability. This can be solved by weaving flat yarns molded from polyester resin, but as is well known, polyester resins have low melt tension and severe cracking occurs during longitudinal-axial stretching, making them unsuitable for flat yarn molding. belongs to.

The present invention aims to solve the above problems.

[Structure of the invention]

(Means for Solving the Problems) The carpet base fabric according to the present invention is woven from a composite flat yarn. A coating 2 made of polyester resin such as terephthalate is laminated. Moreover, in order to mold this composite flat yarn, it can be manufactured by pouring a molten polypropylene resin and pouring out the molten polyester resin on both sides of the flow path.

However, when manufacturing the above composite flat yarn,
There are technical problems to be solved, the first being ensuring sufficient bonding strength between the polypropylene resin and the polyester resin, and the second being preventing post-shrinkage.

In order to ensure the first bonding strength, it is necessary to solve the problem of distortion since the polypropylene resin and the polyester resin have different molding shrinkage rates. As a countermeasure, the thickness of the film molded from polyester resin can be reduced, but the molten viscosity of this type of resin at high temperatures decreases significantly, and it is difficult to form a thin film and bond it.

Therefore, we controlled the flowability in each channel up to the bonding of both resins. As a control factor at this time, if the cross-sectional area and cross-sectional shape of each channel and the flow rate of the resin are fixed, the temperature of the resin may be controlled. In addition, the velocity head of the polypropylene resin serving as the main layer is 1.1 to 1.
5 times was appropriate. The reason for this is that in each flow, there is naturally friction with the wall surface of the flow channel, and there is a lag toward the wall surface. The speed difference is processed using the above-mentioned magnification. By processing in this way, the molten polyester resin is entrained by the molten polypropylene resin with a high water head, and the shear at both interfaces is used to increase the bonding area and improve the bonding strength. This achieves thinning. Furthermore, by keeping the thickness of the coating made of polyester resin having a large molding shrinkage rate within 2 to 40% of the total thickness of the composite flat yarn, distortion during molding can be suppressed.

The temperature as the control factor varies depending on the structure of the die for forming the composite flat yarn and the flow rate. In particular, since the flowability of polyester resin is highly temperature dependent, it is largely a factor that can be obtained through experiment and experience.

In addition, in the process of drawing the composite flat yarn formed by the die, the polyester resin coating is added to the main layer and drawn, so it can be drawn well without causing vertical cracks. .

Next, reduce the second post-contraction (temporal contraction) as much as possible,
We attempted to establish annealing conditions to maintain dimensional stability. This control factor is the temperature and relaxation rate if the rate is determined, but the relaxation rate can be narrowed down to the temperature assuming the maximum amount that does not float. Resin melting point lower than 225°C, preferably 190°C
It was in the range of ~210'C. In particular, if you set it on the high temperature side and bring it close to the melting point of polyester resin, you can process it in a short time, and the surface temperature during processing when applying latex to the back of the product is assumed to be 160 to 170 degrees Celsius, so it will be even higher. Preferably, heat treatment is performed at a temperature.

A carpet base fabric is obtained by weaving the composite flat yarn obtained in the above process in warp and warp directions.

(Example) FIG. 1 shows a carpet base fabric 1 according to the present invention,
The composite flat yarn 2 constituting the base fabric 1 is shown in FIG. 2, and the main layer 3 is made of polypropylene resin, and the coatings 4 and 5 on both the front and back surfaces are made of polybutylene terephthalate resin. FIG. 3 shows a composite extrusion device, which includes a main layer extruder 6 for extruding polypropylene resin.
and a coating extruder 7 for extruding polyester resin are connected to a die 8, and the die 8 has a polypropylene resin inlet 9 on its upper surface as shown in FIG. A flow path 11 is provided from the annular hole 10 leading to the outlet 12 at the lower end, and a pair of polyester resin inlets 13 and 14 are provided on the side surface of the die 8, and each annular hole 15 is connected to the flow path 11. .16 is provided with a flow path 17.18 communicating with the outlet 12, and is provided in the middle of the flow path 11 for the polypropylene resin so that both flow paths 17.18 for the polyester resin merge from both sides thereof. .

The main layer extruder 6 has a diameter of 65φ and L/D=2.
5. This model uses a 30KIilAS motor and a full-flight screw, and the coating extruder 7 is 50φ.
This model uses a L/D = 24.15KVAS motor, special kneading type screw, and vent type.

The extrusion conditions for polypropylene resin are Properties - MFR2, 2, Density 0.90 Temperature - 225 to 230°C The extrusion conditions for polybutylene terephthalate are Properties - Density 1
．． 3 Temperature -240 to 245°C Although the velocity head of both resins in the flow path cannot be measured, the calculated value based on the flow path and flow rate is a total extrusion rate of 48 kg/H, whereas the main layer flow path and coating flow The flow velocity ratio of the channel is 1
．． 3 to 1.35. The ratio of the thickness of both layers is 1:10:1
, the absolute thickness is estimated to be 2μ:20μ:2μ.

Further, the stretching ratio is 7.2 times and the relaxation rate is 11%, so the actual stretching ratio is 6.4 times. Furthermore, the surface temperature during annealing was 200 to 205°C.

When the physical properties of the composite flat yarn 2 obtained under the above conditions were compared with that of a single polypropylene resin flat yarn constituting a conventional carpet base fabric, the data shown in Table I were obtained. In the table, composite flat yarns are abbreviated as composite yarns, and flat yarns made of polypropylene alone are abbreviated as P and P yarns.

Table-I Notes- (E) Thermal shrinkage rate is 130℃, 10 minutes drying oven (G) Surface heat resistance temperature is 1 minute (H) Annealing conditions for dimensional change rate over time depend on each condition (2 Weeks) Next, the above When comparing the physical properties of a base fabric woven with the composite flat yarn 2 obtained by the method described above and a base fabric woven with a flat yarn made of polypropylene resin alone, data as shown in Table H were obtained.

Table - ■ Table 1 above. As shown by (2), the composite flat yarn according to the present invention has higher heat distortion temperature and surface heat resistance temperature than the flat yarn made of polypropylene alone, and can sufficiently withstand latex coating processing. Also,
Since the rate of dimensional change over time is reduced, dimensional stability is maintained.

〔Effect of the invention〕

The carpet base fabric according to the present invention is woven from a composite flat yarn in which a polyester resin coating is laminated on both the front and back sides of a main layer of polypropylene resin, and has improved heat resistance and dimensional stability.

Further, according to the method for manufacturing a carpet base fabric according to the present invention,
By setting the temperatures of the molten metals of polypropylene resin and polyester resin to be lower for the polypropylene resin and higher for the polyester resin, and by making the velocity head slightly higher for the polypropylene resin, we can strengthen the bond between the two types of fat. , the polyester resin coating is thinned to prevent distortion during molding. Furthermore, in the ayu-ring process after being shaped and stretched in this way, by processing at a temperature higher than the melting point of the main layer of polypropylene resin and lower than the melting point of the polyester resin coating,
In order to prevent post-shrinkage, the dimensions are stabilized even in high-temperature environments.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a carpet base fabric according to the present invention, Fig. 2 is a perspective view showing a composite flat yarn constituting the carpet base fabric shown in Fig. 1, and Fig. 3 is a perspective view showing the composite flat yarn shown in Fig. 2. A perspective view showing a composite extrusion device for manufacturing
FIG. 4 is a sectional view showing the die in the apparatus shown in FIG. 3. DESCRIPTION OF SYMBOLS 1... Carpet base fabric, 2... Composite flat yarn, 3... Main layer, 4, 5... Coating, 6... Extruder for main layer. 7...Coating extruder Figure 1 3 Crown layer Figure 3

Claims (1)

[Scope of Claims] 1) A carpet base fabric in which composite flat yarns 2, in which coatings 4 and 5 made of polyester resin are laminated on both the front and back sides of a main layer 3 made of polypropylene resin, are arranged in the warp and warp direction and woven. 2) When the molten polyester resin is joined to both sides of the flow path of the molten polypropylene resin and flows, the temperature of the molten polyester resin is higher than the temperature of the molten polypropylene resin, and the velocity head of the molten polypropylene resin is made higher. In the annealing process performed after the drawing process, the composite flat yarn is treated at a temperature higher than the melting point of the polypropylene resin and lower than the melting point of the polyester resin. A method for producing carpet base fabric by weaving.