JPH111855A - Production of heat-pressed fiber sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat-pressed fiber sheet capable of cleaning up without damaging rolls, improved in workability and facilitymaintaining property and excellent in quality by removing stain attached to the surface of heating rolls immediately after heat from immediately after heat pressing to next heat pressing. SOLUTION: When a fiber sheet 1 constituted of high melting point fiber alone or constituted of high melting point fiber and low melting fiber is heat- pressed with heating rolls, stain attached to the surface of heating rolls immediately after pressing is removed from immediately after heat pressing to next heat pressing to provide the objective heat-pressed fiber sheet. Furthermore, the stain is preferably stripped off by a scraper 2 which comes into contact with heating roll surface and a part which comes into contact with heating roll of the scraper 2 is preferably composed of an elastomer such as silicone rubber having 30-90 spring hardness (HS=JIS A) obtained when measured according to JIS K-6301.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermocompression-bonded fiber sheet that can be operated continuously for a long time and can achieve uniform thermocompression bonding.

[0002]

2. Description of the Related Art A fiber sheet made of a non-woven fabric or the like needs to be improved in strength, dimensional stability, abrasion resistance, thickness uniformity, etc. according to the intended use. One of the means is thermocompression bonding using a heating roll. Is generally adopted.

[0003] In this thermocompression bonding, generally employed is a method in which a fiber web is sandwiched between heating rolls to bond fibers together or a sheet thickness is controlled to be constant.

[0004]

However, when the heating roll is used for a long time and subjected to thermocompression bonding, the polymer and oligomer of the fiber constituents adhere to the portion of the heating roll passing through the fiber sheet, and the film is formed on the roll surface. The dirt in the shape gradually increases, and as a result, the heating efficiency of the heating roll to the sheet decreases, the dirt is transferred to the sheet and the quality of the sheet deteriorates. There is a fundamental defect that the quality of the fiber sheet changes over time due to loss of uniformity and a stable product cannot be supplied.

Further, with the growth of the adhered dirt, there is a problem in processing that removal becomes difficult with time and cleaning in a short time becomes indispensable, resulting in remarkable decrease in workability.

[0006] At this time, the heating rolls are usually used as flat rolls, uneven rolls, or a combination thereof. However, when the heating rolls are periodically cleaned to remove dirt with a hard material, the rolls are damaged. This is a major drawback. In any case, there were major problems in quality, processing, and equipment maintenance.

Therefore, in order to solve the above-mentioned problems, a method of installing a cleaning device such as a wire brush on a heating roll has been conventionally proposed. However, the stain removal property becomes uneven or the removed stain is removed. There is a problem that it cannot be used during sheet processing because it adheres to the sheet.

Further, a method has been proposed in which the surface of the heating roll is subjected to a surface treatment such as plating to make it difficult for dirt to adhere thereto or to facilitate the removal of dirt. However, periodic cleaning outside the sheet processing time is required. In addition, there was a problem that it was costly, and it was not an essential solution.

In view of the background of the prior art, the present invention
Prevents adhesion of dirt to the heating roll, no change in heating efficiency, no transfer of dirt, and no irregularities, enables continuous production for a long time, requires less cleaning time, and rolls for cleaning the rolls An object of the present invention is to provide a method for producing a thermocompression-bonded fiber sheet having excellent workability and equipment maintainability, which are excellent in preventing occurrence of surface scratches, and stable quality.

[0010]

The present invention employs the following means in order to solve the above problems. That is, the method for producing a thermocompression-bonded fiber sheet according to the present invention is characterized in that, when a fiber sheet is thermocompression-bonded with a heating roll, dirt adhering to the surface of the heating roll immediately after the thermocompression bonding is applied immediately after the thermocompression bonding to the next thermocompression bonding. It is characterized by being removed during.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been made as a result of intensive studies to solve the above-mentioned problems in quality, processing and equipment maintenance.
Dirt on the surface of the heating roll is removed during a specific period from immediately after the thermocompression bonding to the next thermocompression bonding, and furthermore, by adopting a specific means called a scraper as the means, it has been found that the above problem can be solved at once. Things.

Conventionally, when a fiber sheet is subjected to thermocompression bonding, a heating roll is used. In this case, the constituents of the fiber sheet, such as a polymer and an oligomer, adhere to the surface of the heating roll and become soiled. The dirt accumulates on the roll and adheres and covers the entire roll of the fiber sheet passing portion in a film form. When the film-like material becomes dirty in this way, the function of the heating roll is hindered, and control of thermocompression bonding cannot be performed.

[0013] That is, the present invention relates to a specific method from the surface of a heating roll being processed to a surface immediately after thermocompression bonding to the next thermocompression bonding, to which dirt composed of deposits such as polymers and oligomers, which are constituents of a fiber sheet, has adhered. A method of peeling between, more preferably a scraper made of an elastic body is employed. Simply put, do not leave in a state where dirt easily accumulates on the surface of the heating roll, and the dirt attached during thermocompression bonding with the heating roll, during a specific period from immediately after thermocompression bonding to the next thermocompression bonding, The scraper is in close contact with the heating roll. For example, if a scraper is kept in close contact with the surface of the heating roll, the thermocompression treatment can be smoothly continued without the accumulation of dirt. The temperature condition of the heating roll referred to here is the target fiber for thermocompression bonding, that is, in the case of the high-melting polymer fiber alone, the melting point of the high-melting polymer fiber, and also in the case of including the adhesive component polymer (including the low-melting polymer fiber). Is between 10 and 12 above the respective melting points of the component polymers.
Crimping at 0 ° C lower temperature. Of course, depending on the polymer, pressure bonding may be performed at a temperature 20 to 50 ° C. lower than the melting point of the fibers constituting the fiber sheet.

That is, the fiber sheet in the present invention may be composed of a high-melting polymer fiber alone or a fiber sheet comprising a high-melting polymer fiber and an adhesive component polymer and / or a low-melting polymer fiber. But it can be used. As a structure of such a fiber sheet, a nonwoven fabric, a woven or knitted fabric, a composite thereof, or the like can be used. As such a fiber sheet, those made of synthetic fibers such as polyolefin, polyester, polyamide, and polyacrylonitrile, and inorganic fibers such as glass fiber and carbon fiber can be used.

According to the present invention, a dirt made of such a polymer is removed.
Preferably, the scraping is performed by a scraper made of an elastic body, but since the surface of the heating roll is naturally heated, the scraper is not a sharp and hard thing like a blade, but is made of an elastic material. Even with a soft material, the precipitated polymer and oligomer can be removed smoothly and effectively.

As the scraper of the present invention, JIS
An elastic body having a spring hardness (Hs = JIS A) of 30 to 90 when measured based on K-6301 not only has a function of physically removing minute dirt on the heating roll, but also has a close contact with the heating roll. It is preferably used because it has both excellent heat resistance and heat resistance and a function of not damaging the heating roll. When the hardness is less than 30, the function of physically removing dirt is deterred. In the case of a scraper having a hardness of more than 90 or a non-elastic material such as metal, the roll surface may be scratched or curved. Contact cannot be made without a gap, and there is a tendency that dirt is left behind. Further, there arises a problem that it is not possible to cope with a change in the roll diameter due to a change in the temperature condition of the heating roll.

The material constituting the scraper of the present invention does not need to be an elastic body having a spring hardness in the range of 30 to 90 in a portion other than the heating roll contacting portion. A composite with a reinforcing material such as a reinforcing cloth made of fibers and further synthetic fibers or the like, that is, a material harder than the above hardness can be used.

The elastic body having the specific hardness referred to in the present invention is not particularly limited, and various rubbers, elastomers such as polyolefin and polyurethane can be used. From the viewpoint of heat resistance, silicone rubber is most preferably used.

Such a scraper accumulates powdery dirt, but such deposits can be easily removed by suction or the like, and there is no need for periodic roll cleaning, which reduces the complexity of the work surface. There is no advantage. Also, in order to achieve both the dirt-removing property and the adhesiveness with the heating roll, and further considering the durability of the scraper, the pressing pressure of the scraper on the heating roll is limited to a range of 0.01 to 4 kg / cm ^2. It is preferred to use. Pressing pressure is 0.01kg
When it is less than / cm ^2, stain stripping, adhesion is insufficient, when it exceeds 4 kg / cm ^2, since the durability of the elastic body constituting the scraper is deteriorated unfavorably.

[0020]

Next, the present invention will be described in detail with reference to Examples.
The present invention is not limited by these.

Example 1 A scraper made of silicone rubber having a spring hardness (JIS A) of 60 and a thickness of 10 mm, as measured in accordance with JIS K-6301, over the entire width of a flat heating roll having a surface temperature of 180 ° C. Pressing pressure 0.
Using a cloth making machine set at 5 kg / cm ² , by a known spunbonding method, the fineness is 5 denier and the basis weight is 10
A polyester filament web of 0 g / m ² was obtained, and subjected to thermocompression bonding at a linear pressure of 50 kg / cm with the above-mentioned heating roll. Further, needle punching was performed to obtain a nonwoven fabric sheet. As described above, the production of the nonwoven fabric sheet was continuously performed for one week, but no dirt was attached to the surface of the heating roll and there was no scratch. Comparative Example 1 A scraper made of silicone rubber having a spring hardness of 60 and a thickness of 10 mm was pressed against a heating roll at a pressure of 0.5.
A non-woven fabric sheet was produced in the same manner as in Example 1 except that the non-woven fabric sheet was not set at kg / cm ² , and the polymer and oligomer stains of the fiber component adhered to the portion of the heating roll passing through the non-woven fabric sheet in only one day. Had the disadvantage that Comparative Example 2 A nonwoven fabric sheet was produced in the same manner as in Example 1 except that a scraper made of silicone rubber having a spring hardness of 20 and a thickness of 10 mm was used. It was possible to confirm the adhesion of dirt in a day.

Comparative Example 3 A nonwoven fabric sheet was produced in the same manner as in Example 1 except that an iron scraper having a spring hardness of 100 was used. There are inherent disadvantages such as uneven removal of dirt every day and abrasion on a part of the surface of the heating roll.

[0023]

According to the present invention, when a fiber sheet is thermocompression-bonded with a heating roll, the deposition of dirt such as polymers and oligomers deposited from the fiber sheet constituents on the roll surface is prevented and the roll is damaged. Cleaning can be performed without any trouble, and the thermocompression treatment for a long time can be stably maintained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an arrangement of a heating roll and a scraper used in a method for producing a thermocompression bonding fiber sheet of the present invention.

[Explanation of symbols]

 1: fiber sheet 2: scraper

Claims (8)

[Claims] When a fiber sheet is thermocompressed with a heating roll, dirt adhering to the surface of the heating roll immediately after the thermocompression bonding is removed immediately after the thermocompression bonding and before the next thermocompression bonding. Production method of thermocompression bonded fiber sheet. 2. The method for producing a thermocompression-bonded fiber sheet according to claim 1, wherein the method of removing dirt adhering to the surface of the heating roll is a method of stripping dirt with a scraper in contact with the surface of the heating roll. 3. A portion of the scraper which comes into contact with a heating roll is made of an elastic body having a spring hardness (Hs = JIS A) of 30 to 90 as measured according to JIS K-6301. The method for producing a thermocompression-bonded fiber sheet according to claim 1. 4. The method according to claim 3, wherein said elastic body is silicone rubber. 5. The method for producing a thermocompression-bonded fiber sheet according to claim 3, wherein the elastic body is formed of a composite with a reinforcing fiber structure at a portion other than a portion in contact with the heating roll. . 6. The method for producing a thermocompression-bonded fiber sheet according to claim 1, wherein a pressing pressure of the scraper against a heating roll is 0.01 to 4 kg / cm ² . 7. The thermocompression bonded fiber sheet according to claim 1, wherein the heating temperature of the heating roll is 10 to 120 ° C. lower than the melting point of the polymer constituting the fiber sheet. Manufacturing method. 8. The method for producing a thermocompression-bonded fiber sheet according to claim 7, wherein the fiber sheet is composed of a high-melting fiber alone or a high-melting fiber and a low-melting fiber.