JPH11164769A - Carpet and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carpet having a high-strength packing material which is not damaged even when repeatedly peeled and re-bonded, and a method for manufacturing the same. SOLUTION: A packing material slurry 21 containing an aqueous resin dispersant and at least either one of a watar-hardenable inorganic powder and a water-nonhardenable inorganic powder is continuously molded into the shape of a sheet, and a carpet based material 12 is continuously laid on the sheet to form a laminate 10. Which moving the laminate 10 the packing material 21 is heated from the underside to expand the packing material 21 at an expansion ratio of 1.02 to 1.5, and is then dried and hardened to manufacture the carpet 1 continuously.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carpet formed by laminating and bonding a backing material and a carpet base material, and a method for producing the carpet.

[0002]

2. Description of the Related Art A tile carpet laid on a floor of a building or the like is manufactured by laminating and bonding a backing material to a carpet substrate on which piles are planted or a needle-punched carpet substrate. I have. Conventionally, as a method of manufacturing a carpet, a backing material containing an aqueous resin dispersion, a hydraulic inorganic powder and a non-hydraulic inorganic powder is continuously formed, and then the carpet base material is bonded and the backing material is dried. A method of curing is known (JP-A-5-254081, JP-A-5-54081)
254,082, JP-A-6-154070). However, these conventional methods have a drawback in that, when water and the like in the aqueous dispersion of the backing material are evaporated and dried, bubbles are formed in the backing material, and the strength of the obtained backing material is reduced. .

[0003]

The tile carpet is used by laying it on the floor of a store, office, residence, or the like. However, when the backing material strength of the tile carpet is low, for example, when the load is repeatedly applied by the chair caster or when a heavy object such as a copy machine is placed, the change in the thickness or the size due to the load is caused. May occur. On the floor of the access floor, the carpet and the floor may be bonded with an adhesive to prevent the carpet from shifting. However, in this case, when peeling and re-attachment of the carpet are repeated, for example, by changing the pattern of wiring under the carpet, there is a problem that the backing material loses adhesive strength and the material is destroyed.

[0004] On the other hand, if the strength of the adhesive is reduced or the use of the adhesive is eliminated in order to cope with the above, the fitting to the floor surface becomes insufficient. In addition, there is a problem that the carpet is shifted during long-term use and the top surface of the carpet becomes uneven.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a carpet having a high-strength backing material, which does not damage the backing material even when peeling and re-adhering are repeated, and a method of manufacturing the carpet. Is what you do.

[0006]

According to the first aspect of the present invention, a backing material containing an aqueous resin dispersion and at least one of a hydraulic inorganic powder and a non-hydraulic inorganic powder is bonded to the backing material. A carpet comprising a carpet substrate, wherein the backing material has an expansion ratio of 1.02.
It is a carpet characterized by being -1.5.

The most remarkable point in the present invention is that the expansion ratio of the backing material is 1.02 to 1.5. Those with an expansion ratio of less than 1.02 cannot be manufactured,
If it exceeds 300, there is a problem that the strength is reduced.

According to the present invention, there is provided a carpet having a high strength backing material which does not damage the backing material even if the backing material is repeatedly adhered to an access floor floor or the like as described above, and peeled and re-adhered repeatedly. can do.

In the present invention, the material of the backing material comprises an aqueous resin dispersion (aqueous emulsion) and at least one of inorganic powders of hydraulic or non-hydraulic inorganic powder. Examples of the aqueous resin dispersion include an acrylic copolymer dispersion, an acrylic-styrene copolymer dispersion,
Further, there are dispersions of vinyl acetate polymer, vinyl acetate-ethylene copolymer, vinyl chloride copolymer, styrene-butadiene copolymer, urethane polymer, acrylonitrile-butadiene copolymer and the like.

As the hydraulic inorganic powder, there are Portland cement, alumina cement, gypsum and the like. Non-hydraulic inorganic powders include silica sand, calcium carbonate, magnesium carbonate, clay, talc, mica, titanium oxide, zinc oxide, barium sulfate, aluminum hydroxide,
Magnesium hydroxide, glass balloon, fly ash, perlite, etc.

The above-mentioned hydraulic inorganic powder or non-hydraulic inorganic powder is 100% by weight of an aqueous resin dispersion (resin solid content).
Is preferably added in an amount of 300 to 600% by weight. If the content is less than 300% by weight, there is a problem that the resin content of the aqueous dispersion becomes high, the drying / curing time becomes long, and the rigidity (toughness) of the backing material is low, so that workability at the time of construction is deteriorated. . On the other hand, if the content exceeds 600% by weight, the backing material becomes brittle and easily cracked, and the flexibility as the backing material is not exhibited, so that there is a problem that practicality is reduced.

Next, as a method of manufacturing the carpet, a backing material slurry containing an aqueous resin dispersion and at least one of a hydraulic inorganic powder and a non-hydraulic inorganic powder is continuously formed into a sheet. Then, a carpet substrate is continuously laminated thereon to form a laminate, and then the laminate is moved and heated and dried from below the backing material to move the backing material to a foaming ratio of 1. There is a method for producing a carpet, characterized in that the carpet is continuously foamed and hardened to produce a carpet.

The most remarkable point in the present manufacturing method is that the carpet is continuously manufactured as described above, and the laminate is heated and dried from below the backing material. Is expanded, and the expansion ratio is set to 1.02 to 1.5. During the heating and drying, the backing material foams and hardens.

The foaming of the backing material is adjusted so that the internal temperature of the backing material is 85 to 100 ° C. If the temperature is lower than 85 ° C., the foaming rate is low to obtain the above-mentioned expansion ratio of 1.02 or more, and the production efficiency is low. on the other hand,
If the temperature exceeds 100 ° C., the foaming speed becomes too fast, and the foaming ratio exceeds 1.5, so that a desired carpet cannot be obtained.

Further, the above foaming is caused by the fact that the water in the aqueous resin dispersion of the backing material evaporates by the above-mentioned heating, and bubbles remain in the portion where the water was present.
Is formed. According to this manufacturing method, an excellent carpet as described above can be easily manufactured.

Next, a specific example of manufacturing the carpet of the present invention will be described. In the production of carpet, the composition of the backing material is first thoroughly mixed by a mortar mixer, a mixing pot equipped with a stirrer, a high-speed disper, or the like so that the composition is uniformly mixed and dispersed.

Next, the slurry is formed into a sheet on a material that is easily peelable, for example, a Teflon-based endless belt. Means for forming the slurry into sheets are as follows:
Use a knife coater, roll coater, or the like. In order to form a sheet, if the slurry viscosity is high, it will not flow easily.
If the viscosity of the slurry is too low, a predetermined thickness cannot be obtained. Therefore, it is preferable to adjust the viscosity with a diluent (water).

As the carpet base material, for example, nylon, polyester,
A tufted synthetic resin fiber such as polypropylene or a needle-punched fiber itself can be used.

In addition, the carpet base material is bonded to a backing material in order to improve pile removal (stripping strength) and fuzziness (fuzz grade) of fibers when used after being laid on the floor. In some cases, a material called a filler is applied. SBR latex, EV as filler
An aqueous resin dispersion such as an A emulsion or an acrylic emulsion is used. As a method of applying the filler, there is a knife coater method, spray application, dipping application roll coat application and the like.

In the application of the filler to the carpet base material, the viscosity of the latex or emulsion is adjusted with a thickener or the like in order to control the amount of application, and the application amount to the fiber is adjusted. Further, a foaming agent can be added to the filler, or foaming can be performed by using a foaming machine, and the application amount can be adjusted by the foaming ratio. The appropriate amount of the filler is different depending on the adhesive strength of the filler to the carpet substrate, but is preferably about 50 g / m ² to 300 g / m ² (after drying).

There is a case where the material coated with the filling agent is dried and then bonded to a backing material, and a case where the material is bonded in an undried so-called wet state. Considering the strength and fuzz), the latter is better.

It is preferable to insert a nonwoven fabric between the sheets in order to improve the strength of the backing material formed into a sheet and to maintain dimensional stability (see the embodiment). In the method, first, a composition slurry of a backing material is formed into a sheet. Next, the above nonwoven fabric is placed thereon, and the composition slurry is further placed thereon to form a sheet. The non-woven fabric may be a glass non-woven fabric or a reticulated material, or may be an organic non-woven fabric such as polyester or polypropylene and a reticulated material.

If the backing material has sufficient strength,
The insertion of the nonwoven fabric may be omitted. The slurry composition of the backing material to be formed into a sheet is composed of the first layer (lower side) and the second layer.
The layers (carpet substrate side) may have the same composition,
In addition, the composition ratio can be changed in some cases. Also,
The second layer can be omitted.

Next, the backing material and the carpet base material are bonded together. At this time, the carpet coated with the filler on the back surface is placed along the backing material and pressed with a nip roll to improve the adhesion between the carpet base material and the backing material and set the thickness to an arbitrary value.

The laminate having the set thickness is subjected to a heating and drying process. The expansion ratio shown in the present invention is determined by the conditions of the drying zone. In other words, the water of the composition slurry containing water is heated in the drying process, evaporates from the slurry and escapes,
The backing material becomes a sheet of the non-volatile component. Due to the evaporation of the water, air bubbles remain in the portion where the water was present,
A foamed backing material is formed.

There are various heating and drying methods, for example, drying with hot air, radiant heat drying with an electric heater, a far infrared heater, etc., internal heat drying with high frequency and microwave, and heat transfer drying with a hot plate. . In the method of the present invention, for example, via a belt of a belt conveyor,
Heat the underside of the backing material. Therefore, the temperature of the backing material rises due to the conduction of heat from below,
Water evaporates and scatters to the carpet substrate side. Thereby, the bubbles in the backing layer are controlled uniformly.

The temperature conditions in the heating and drying steps affect the magnitude of the expansion ratio in the backing material. When the drying temperature is increased, the productivity (line speed) is increased, but the expansion ratio is increased, and the predetermined backing material strength cannot be achieved. Also, lowering the drying temperature lowers the expansion ratio, but lowers productivity. For this reason, in the heating and drying processes, the moisture can be efficiently removed by decreasing the water content of the backing material and increasing the temperature stepwise so that the expansion ratio does not change.

In order to increase the productivity, it is preferable to adopt a method in which the temperature of the hot plate is increased stepwise, and the carpet laminated from the endless belt is peeled off and then passed through a hot blast stove. Thereby, residual moisture can be efficiently removed. The hot air temperature at this time is 90
At a temperature between ℃ and 150 ℃, the higher the temperature, the higher the productivity. However, it is preferable to carry out at a temperature that does not deteriorate the backing material and the carpet.

Further, regarding the drying of the backing material, the case where the drying is completed only with the first layer and the case where the first layer is heated and
After drying, the second layer may be applied thereon and heated and dried stepwise. In the case of the same thickness, the drying speed in the latter two stages is slightly faster.

Immediately after leaving the drying step, the backing material is in a heated state. Then, when the aqueous resin dispersion is applied to the lower surface of the backing material (the surface separated from the endless belt) at about 5 to 30 g / m ² (per resin solid content), the water content of the aqueous dispersion is evaporated by preheating after drying. , A thin resin layer can be formed on the lower surface. Even without this resin layer, there is no problem in the load bearing strength of the carpet and the adhesive strength when the carpet is reattached, but there is an effect of improving the strength of the backing material.

Also, by changing the type of the resin layer,
For example, if the adhesive is applied to the lower surface of the carpet, the operation of applying the adhesive to the floor surface during the construction of the tile carpet can be omitted. Further, by applying an anti-slip agent (a non-adhesive type having an increased friction coefficient), a tile carpet of a laid-down system can be provided.

Here, the expansion ratio is defined as the volume A after evaporating and removing water from the backing material composition by heating.
Is divided by the volume B when this composition is cured without heating (A / B). That is, the volume B
Is the volume of the backing composition after 28 days of curing at room temperature.

In addition, foam is entrained in the backing material slurry, which is formed into a sheet, and when the heating and drying steps are performed, the foaming ratio increases. In order to prevent this, it is necessary to reduce the mixing of bubbles as much as possible. The reason why bubbles are mixed is that when stirring the backing material slurry, air is entrapped at this stage in order to mix with a mixer having a high shearing effect.

The aqueous resin dispersion is produced by polymerization using a dispersant such as a surfactant, an emulsifier, or a protective colloid agent such as a water-soluble resin in order to disperse the resin in fine particles in water. At this time, in order to stably disperse the fine particles in water, these dispersants are often contained in excess. This aqueous resin dispersion generates bubbles only by stirring. For this reason, bubbles are present in the backing material slurry for the above-described reason. Therefore, in order to prevent these bubbles from being mixed into the sheet of the backing material,
It is also useful to add an antifoam during mixing to reduce foam.

That is, according to the third aspect of the present invention, an antifoaming agent is used in an amount of 0.3 to 100% by weight based on the aqueous resin dispersion.
It is preferable to add 5% by weight. Thereby, foaming of the backing material slurry can be prevented. 0.
If it is less than 3% by weight, defoaming is not sufficient. On the other hand, 5% by weight
If the ratio exceeds, there is a problem that the strength of the backing material is reduced.

The defoaming agent may be added in advance to the raw aqueous resin dispersion or may be added when the powder and the liquid are mixed. As the defoaming agent, for example, a general one for adding an emulsion is used. These include silica-silicone, silicone metal soap, amide, ester, polyether, polyglycol, organic phosphoric acid,
It is often used in one or more mixed systems of higher alcohols and oil-soluble systems.

Next, as in the fourth aspect of the present invention, the water-reducing agent is added in an amount of 0.5 to 100% by weight to the hydraulic inorganic powder.
It is preferable to add 5% by weight. The use of a water reducing agent can reduce the unit water volume and the water-cement ratio. For this reason, the drying time can be reduced and the generation of bubbles can be reduced.

The water reducing agent generally belongs to a group of surfactants. The water reducing agent has a hydrophobic group and a hydrophilic group in its molecule, and has a surface active action such as dispersion, wetting, foaming, and emulsification depending on the balance. It is said that is decided. Some or dozens of cement particles aggregate with each other to form aggregates (flocs) of the particles. Due to the strong cohesion between the particles, the cement particles do not disperse into individual states simply by mechanical stirring in water. A surfactant, which is a main component of the water reducing agent, for example, calcium ligninsulfonate dissociates into anions and cations in water and exhibits strong anionic activity.

This active anion is adsorbed on the cement particle interface to form a charged layer on the cement particle surface, and the cement particles are individually dispersed by the mutual repulsion of the electrostatic particles. Air bubbles are released. This contributes to the fluidity of the cement paste and consequently reduces the amount of water added.

Examples of the water reducing agent include resin soap, synthetic surfactant, lignin sulfonate gluconate, polycondensate of naphthalenesulfonic acid formalin, polycondensate of melaminesulfonic acid formalin, polycarboxylic acid, polyaminosulfonic acid salt and the like. Is used. If the amount is less than 0.5% by weight, the water reducing effect is small. In addition, more preferably 1-3% by weight
It is.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments and comparative examples according to the present invention will be described in detail. Embodiment 1 As shown in FIG. 2, a carpet 1 obtained in this embodiment
Consists of a backing material 11 and a carpet substrate 12 adhered to the backing material 11. The backing material 11
It comprises an aqueous resin dispersion and at least one of inorganic powders of hydraulic inorganic powder or non-hydraulic inorganic powder. Also,
The expansion ratio of the backing material 11 is 1.02 to 1.5. As shown in FIG. 2, the backing material 11 has bubbles 111 generated by foaming, while the carpet base material 12 has flocking 13.

Next, an apparatus and a method for manufacturing the carpet will be described with reference to FIG. First, the manufacturing apparatus includes a conveyor belt 55 made of tetrafluoroethylene and a first tank 2 containing a slurry-like first backing material 21.
And a second tank 3 containing a slurry-like second backing material 31 and an electric heater 5 provided below the conveyor belt 55. Further, it has a group of rollers 45 for supplying the carpet base material 12 onto the backing material, and a dipping roll 41 for applying a coating agent 49 for filling the carpet on the back surface of the carpet base material 12.

Then, the carpet 1 is
In the manufacture of the conveyor belt 55, the conveyor belt 55 is moved by the drive roller 551, the slurry-like first backing material 21 is continuously supplied from the first tank 2 thereon, and the slurry is made constant by the doctor knife 53. Then,
A glass nonwoven fabric 25 is overlaid on the first backing material 21 sent at a constant thickness via a roller 251, and then a slurry-like second backing material 31 from the second tank 3 is placed on the glass nonwoven fabric 25. Supply continuously. Then, the thickness of the second backing material 31 is made constant by the doctor knife 54.

Next, on the second backing material 31,
The carpet substrate 12 coated with the coating agent 49 is laminated to form a laminate 10. At this time, the carpet base material 12 is pressed by the pressing roll 47. Next, the lower surface of the laminate 10 continuously fed as described above is heated by the electric heater 5 from below the conveyor belt 55.

By this heating, the first and second backing materials 21 and 31 are heated and dried, and the water therein evaporates and escapes to the outside, so that the backing material foams. Then, finally, the first and second backing materials 21 and 31 are hardened. Thereby, the carpet 1 shown in FIG. 2 can be manufactured.

Next, a specific example of carpet production will be described. Nylon tufted carpet base material 12 (basis weight 80
0 g / m ² ) on the back of the carpet substrate 12
Acronal 2716D as a coating material 49 for a surface substrate
(Mitsubishi Chemical BASF, trade name, acrylic ester-styrene copolymer aqueous emulsion solids concentration 48%,
(Tg 24 ° C.) is applied by the dipping roll 41 described above. The coating amount of the base material coating agent is 150 g / m.
² (in terms of solid content).

On the other hand, Acronal S400 (trade name, manufactured by Mitsubishi Kagaku BASF, an aqueous emulsion of acrylate-styrene copolymer, Tg
(−21 ° C.) 100 parts by weight of Portland cement (Mitsubishi Materials Corporation, Portland Cement) as a hydraulic inorganic powder, 200 parts by weight, and calcium carbonate as a non-hydraulic inorganic powder as an aggregate (Dowa Mining Co., Ltd., KD- 10
0) 250 parts by weight, 2 parts by weight of cement water reducing agent Mighty 150 (Kao Corporation, trade name), 1 part by weight of defoamer Nopco 8034 (San Nopco Co., trade name), and 30 parts by weight of water for viscosity adjustment did. Next, these were mixed for 10 minutes by a mixer with a stirring blade to obtain slurries 21 and 31 for the first and second backing materials having a slurry concentration of 78%.

Next, the slurry-like first backing material 21 is poured from the first tank 2 onto the conveyor belt 55 as shown in FIG. Then, the slurry-like backing material 21 is adjusted to a thickness of 1.5 mm by the doctor knife 53. The conveyor belt 55 is driven endlessly, and the first backing material 21 whose thickness is controlled moves as a uniform sheet.

Next, on the surface of the first backing material 21, a glass nonwoven fabric (basis weight 50 g) 25 for reinforcement is placed. Furthermore, the slurry-like second backing material 31 is poured from the second tank 3 from above, and the thickness is set by a doctor knife 54 so that the entire sheet thickness becomes 2.5 mm. Next, the carpet substrate 12 coated with the coating agent 49 is placed and pressed on the back surface, and the thickness is controlled to 6.5 mm by the roll 47 to obtain the laminate 10.

The laminate 10 moves while being placed on the conveyor belt 55 and reaches above the electric heater 5.
Here, the carpet 1 is heated and dried, and the water in the backing material evaporates and evaporates to foam and harden, thereby forming the carpet 1. In addition,
The electric heater is heated to 95 ° C. The sufficiently dried and cured carpet is separated from the belt and then cooled. Then, it is stamped into a size of 500 × 500 mm. The overall thickness of this carpet was 6.5 mm and the weight was 920 g. This carpet is used as a tile carpet.

Next, in order to examine the expansion ratio of the backing material, only the backing material was allowed to flow on a conveyor belt under the same conditions to obtain a sample of a foamed sheet-like backing material. This sheet had a thickness of 2.3 mm, and was cut into a size of 200 × 200 mm. Then, as shown in FIG.
It was placed in a metal frame 6 having a recess 611 of 0 × 200 mm and was pressed at 50 kg / cm ² for 10 minutes at room temperature by a pressure press.

After that, when this was taken out and its thickness was measured, it was 2.1 mm. Therefore, the expansion ratio of this sheet was 2.3 / 2.1 = 1.1 times. In addition,
The metal frame 6 for measuring the expansion ratio comprises a lower die 61 having a recess 611 for receiving the sheet 19 and an upper portion 62 having a convex portion 621 for pressing the sheet 19.

Next, the same backing material slurry as above was poured into a mold with a thickness of 2.5 mm, and after curing at room temperature 23 ° C. for 28 days, the thickness of the sheet was 2.1 mm. Similarly, after the sheet was pressed by the metal frame 6 and the thickness was measured, it was 2.1 mm, and no change in the thickness was observed.

Next, in order to measure the peel strength, a peel-up bond for tile carpet (manufactured by Mitsubishi Burlington, CT bond) was applied on a slate plate 500 × 500 mm so as to have an application amount of 100 g / m ^2. Apply with a flat spatula and air dry until it is clear. Next, the above-mentioned carpet was put on it and it was adhesively fixed. Next, JI
Using an S-caster tester, the test was performed under the conditions of R100, 90 kg load, and 5000 rpm. And the thickness reduction rate of the said backing material was determined by the following four-step evaluation. As a result, in the case of the present example, the reduction rate of the thickness of the backing material portion was 5% or less, and sufficient strength for practical use was obtained.

Next, the sample after the caster test was peeled off from the slate plate. At this time, the state of destruction of the backing material was visually observed, and judged by the following four-step evaluation. In the case of this example, there was no "take off" of the backing material to the slate bonding surface. Table 1 shows these conditions and measurement results.

The caster test was conducted according to JIS L190
Based on 4-5, R100, 90kg weight, 500
Performed 0 times.

Judgment × Reduction rate of backing material thickness 30% or more △ ”“ 20% or less ”” 10% or less ◎ ”” 5% or less

Peeling test The state of destruction of the backing material is visually determined. Judgment × The backing material is broken and is taken on the slate plate side. △ Destruction of the backing material was very small, with an area of 10% or less ○ “”, dotted, “2% or less ◎” ”, none

Embodiments 2 to 7 and Comparative Examples 1 to 4 Tile carpets were manufactured and evaluated under the conditions shown in Tables 1 and 2 in the same manner as in Embodiment 1. The drying time was set so that the residual moisture content of the backing material became constant. In Example 7, the thickness of the slurry sheet was 1.5 mm for the first layer (belt side layer) and dried at 95 ° C. for 10 minutes. Next, a second layer was coated thereon by 1.0 mm to form an overall sheet thickness of 2.5 mm.
mm (see Table 1) and dried for 13 minutes.

"Sumikaflex 401" (* 1) as an aqueous resin dispersion in Tables 1 and 2 was obtained from Sumitomo Chemical Co., Ltd., "Ethylene-vinyl acetate copolymer resin aqueous emulsion, Tg-18". ° C ”. Alumina cement (* 2) is "Alumina cement No. 1" manufactured by Denki Kagaku Kogyo Co., Ltd. in order to shorten the drying and hardening time of the backing material.

As can be seen from both tables, it can be seen that Examples 1 to 7 according to the present invention are superior to Comparative Examples 1 to 4 in caster test, re-peeling test and productivity.

[0062]

[Table 1]

[0063]

[Table 2]

[0064]

According to the present invention, it is possible to provide a carpet having a high-strength backing material in which the backing material is not damaged even if peeling and re-adhering are repeated, and a method of manufacturing the carpet.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a carpet manufacturing apparatus according to a first embodiment.

FIG. 2 is an explanatory diagram of a carpet according to the first embodiment.

FIG. 3 is an explanatory diagram of a foaming magnification measuring device according to the first embodiment.

[Explanation of symbols]

 1. . . Carpet, 10 . . Laminate, 11. . . Backing material, 12. . . Carpet substrate, 21. . . First backing material, 31. . . 4. second backing material; . . Electric heater, 55. . . Conveyor belt,

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FIB29L 7:00 9:00

Claims (4)

[Claims] 1. A carpet comprising a backing material containing an aqueous resin dispersion and at least one of a hydraulic inorganic powder and a non-hydraulic inorganic powder, and a carpet substrate adhered to the backing material. A carpet, wherein the backing material has an expansion ratio of 1.02 to 1.5. 2. A backing material slurry containing an aqueous resin dispersion and at least one of a hydraulic inorganic powder and a non-hydraulic inorganic powder is continuously formed into a sheet,
Next, a carpet substrate is continuously laminated thereon to form a laminate, and then the laminate is heated and dried from below the backing material while moving the laminate to reduce the foaming ratio to 1.02. A method for producing a carpet, characterized in that the carpet is continuously foamed and cured to 1.5 to produce a carpet. 3. The method for producing a carpet according to claim 2, wherein 0.3 to 5% by weight of an antifoaming agent is added to the aqueous resin dispersion. 4. The method for producing a carpet according to claim 2, wherein a water reducing agent is added to the hydraulic inorganic powder in an amount of 0.5 to 5% by weight.