KR20130007752A - Manufacturing method for non-asbestos sheet and gasket - Google Patents

Abstract

PURPOSE: A manufacturing method of a non-asbestos sheet is provided to obtain environmentally-friendly properties, dispersity and processability of a gasket sheet composition by mixing an opening-treated reinforcing fiber and inorganic filler without using an organic solvent. CONSTITUTION: A manufacturing method of a non-asbestos sheet comprises: a step of first primary mixing aramid fiber, glass fiber and kaolin in a tumbler; a step of secondary mixing the first mixture, acrylonitrile butadiene rubber, natural rubber, metal oxide and stearic acid in a kneader; a step third mixing the second mixture and a crosslinking agent in a roll mill; and a step of molding the third mixture into a sheet with the thickness of 1-2 mm. A manufacturing method of a non-asbestos gasket comprises a step of molding the non-asbestos sheet to a gasket in a high temperature and high pressure press.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a non-asbestos sheet,

The present invention relates to a non-asbestos sheet and a method of manufacturing a gasket. More particularly, the present invention relates to a non-asbestos sheet and a gasket which can be produced in a non-asbestos gasket by using a dry process without using an organic solvent, And a manufacturing method thereof.

Conventionally, a non-asbestos gasket is produced by kneading a nitrile rubber swelled with an organic solvent, a non-asbestos inorganic fiber, a rubber additive, a vulcanizing agent and an inorganic filler, and then heating and rolling the mixture between the hot roll and the cooling roll to produce a gasket.

However, in the conventional manufacturing method as described above, there is a problem in the safety of workers due to the volatile substances harmful to the human body which are generated in the step of swelling the rubber using an excessive amount of organic solvent and the step of collecting the organic solvent , The swelling process, the mixing process, and the molding process, the manufacturing process is very complicated and the manufacturing time is excessively long.

On the other hand, the non-asbestos-based sheet gasket described in Japanese Patent Laid-Open No. 2008-0274053 is formed by mixing fibers, graphite, and rubber together with water and then stacking and integrating them in a hot press.

The joint sheet using fibers other than asbestos described in Japanese Patent Laid-Open Publication No. 2005-0281463 and its manufacturing method are produced by kneading fibers, rubber expanded by a solvent, rubber chemicals, active clay or acid clay, Thereby manufacturing a joint sheet.

The composition for forming a joint sheet, the joint sheet and the manufacturing method thereof described in Japanese Patent Application Laid-Open No. 2000-0034467 are prepared by heat-rolling a composition comprising non-asbestos-based inorganic fibers, nitrile rubber and toluene as an organic solvent between hot and cold rolls Thereby manufacturing a joint sheet.

Japanese Patent Laid-Open Publication No. 1993-0162157 discloses a method of producing a joint sheet, which comprises mixing a mixture obtained by mixing glass fiber, polyamide fiber, natural rubber or synthetic rubber dissolved in an organic solvent and a filler between a cold roll and a hot roll, Sheet.

However, the above-mentioned non-asbestos gasket is manufactured by using a solution method in which rubber is swelled and mixed in an organic solvent for mixing excess filler and fiber, and thus the rubber composition swollen with an organic solvent is used There is an advantage in that an excessive amount of filler can be mixed. However, there are problems such as a decrease in the mechanical strength of the rubber due to the swelling and a decrease in the working environment due to the use of the organic solvent.

Further, the manufacturing process for forming the non-asbestos gasket takes at least two to three days, and the productivity and economical efficiency of the manufacturing process is very low, resulting in an increase in the manufacturing cost, and ultimately the price competitiveness is significantly lowered Causing problems.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made in order to solve the problems of the prior art described above, and it is an object of the present invention to provide a reinforcing fiber- There is provided a method of manufacturing an asbestos sheet and a gasket, which is configured to be more environmentally friendly, significantly increase productivity, and reduce manufacturing cost by applying a compaction process at intervals of 1 to 10 mm on a sheet to ensure uniformity of thickness and stability. It has its purpose.

In order to accomplish the above object, the present invention provides a method of manufacturing a composite material, comprising: a first mixing step of mixing aramid fiber, glass fiber and kaolin in a dumbbell; A second mixing step of mixing the first composition of the first mixing step with acrylonitrile butadiene rubber, natural rubber, metal oxide, stearic acid in a kneader; A third mixing step of mixing the second composition of the second mixing step and the cross-linking agent in a roll mill; And a sheet forming step of forming a third composition of the third mixing step into a sheet having a thickness of 1 to 2 mm, characterized in that the aramid fiber and the glass fiber are subjected to high- The sheet is mixed with kaolin after the opening treatment, and the surface of the sheet is subjected to compaction at intervals of 1 to 10 mm in the sheet forming step.

In the present invention, the sheet is formed into a gasket in a high-temperature and high-pressure press, thereby providing a method of manufacturing an asbestos gasket.

The present invention having the above-described configuration can provide an eco-friendly, productivity, and efficiency that can be remarkably increased, and the manufacturing cost can be significantly lowered, thereby enhancing cost competitiveness.

Hereinafter, preferred embodiments of the present invention will be described in detail.

Generally, the non-asbestos sheet is prepared by mixing aramid fibers, glass fibers and kaolin in a dumbbell in a first mixing step (S10), and mixing the first composition of the first mixing step (S10) After the acrylonitrile butadiene rubber, the natural rubber, the metal oxide and the stearic acid are mixed in the kneader, the second composition of the second mixing step (S20) and the cross-linking agent are mixed in a roll mill in the third mixing step (S30) And the third composition of the third mixing step S30 is formed into a thickness of 1 to 2 mm in the molding step S40.

The non-asbestos gasket is manufactured through a gasket molding step (S50) in which the sheet of the sheet forming step (S40) is molded in a high-temperature and high-pressure press.

When the inorganic filler and the reinforcing fiber are excessively used without using an organic solvent in the production of the non-asbestos sheet and the gasket as described above, the dispersibility of the inorganic filler or the reinforcing fiber is deteriorated and the processability is lowered, And the manufacturing process itself becomes difficult, for example, the uniformity of the product thickness is reduced during the molding of the sheet and gasket.

However, the present invention is configured to solve the dispersibility and the workability by mixing the reinforcement fibers and the inorganic filler in a first mixing step (S10) after preliminary processing for opening and opening, and then mixing with other base materials.

Further, in order to ensure uniformity and stability of the sheet thickness in the sheet forming step (S40), the present invention is configured to solve the problem of uniformity and stability of product thickness by applying a compaction process at intervals of 1 to 10 mm on a sheet .

In the first mixing step (S10) according to the present invention, an opening operation is performed for blowing high-pressure air to the reinforcing fiber to loosen the fiber lump. This opening operation prevents the aggregation of the fibers, . ≪ / RTI >

At this time, in the present invention, the opening reinforced fibers are mixed with the inorganic filler in the dumbbra for 10 to 20 minutes, thereby preventing aggregation of the reinforcing fibers and improving the dispersibility by uniform mixing of the inorganic filler and the reinforcing fibers.

Then, a mixture of reinforcing fiber and inorganic filler, acrylonitrile butadiene rubber, natural rubber, metal oxide, and stearic acid are kneaded in a kneader mixer at 100 to 120 ° C for 10 to 15 minutes to form an asbestos composition .

Here, in the sheet forming step (S40) according to the present invention, the above non-asbestos composition is formed into a sheet having a thickness of 1 to 10 mm while injecting a crosslinking agent in a roll mill at 60 to 80 ° C, So that uniformity of sheet thickness can be ensured during sheet molding of a composition containing an excessive amount of an organic filler and an inorganic filler.

Also, in the present invention, the sheet thus formed and molded is molded in a hot press at a temperature of 150 to 170 DEG C and a temperature of 150 to 180 kg / cm < ² > for 5 to 10 minutes.

20 parts by weight of aramid fibers and 40 parts by weight of glass fibers were subjected to high-pressure air-opening treatment with respect to 100 parts by weight of a base material composed of 70 parts by weight of acrylonitrile butadiene rubber and 30 parts by weight of natural rubber. Then, 300 parts by weight of kaolin And the mixture was kneaded at 100 to 120 ° C for about 12 minutes in a compound kneader kneader together with a composition composed of 100 parts by weight of the substrate, 5 parts by weight of the metal oxide and 1 part by weight of stearic acid to prepare a compound .

The kneaded compound in the kneader was added to 3 parts by weight of organic peroxide as a cross-linking agent in 100 parts by weight of the base material in a roll mill and uniformly mixed to prepare a 2 mm thick sheet. And is put into a mold having a thickness of 2 mm and press-molded under a press condition of 155 캜 and 170 kg / cm ² for about 5 minutes to prepare a gasket sheet.

40 parts by weight of aramid fibers and 40 parts by weight of glass fibers were subjected to high-pressure air-opening treatment with 100 parts by weight of a base material composed of 80 parts by weight of acrylonitrile-butadiene rubber and 20 parts by weight of natural rubber, And the mixture was kneaded in a compound kneader kneader at 100 to 120 ° C for about 15 minutes together with a composition composed of 100 parts by weight of the base material, 5 parts by weight of the metal oxide and 1 part by weight of stearic acid to prepare a compound.

The kneaded compound in the kneader was kneaded in an amount of 3 parts by weight of organic peroxide as a crosslinking agent to 100 parts by weight of the base material in a roll mill and uniformly mixed to prepare a sheet having a thickness of 2 mm. And is put into a mold having a thickness of 2 mm and press-molded under a press condition of 155 캜 and 170 kg / cm ² for about 5 minutes to prepare a gasket sheet.

Comparative Example  One

A composition composed of 20 parts by weight of an aramid fiber, 40 parts by weight of glass fiber, 300 parts by weight of kaolin, 5 parts by weight of a metal oxide and 1 part by weight of stearic acid with respect to 100 parts by weight of a base material composed of 70 parts by weight of acrylonitrile butadiene rubber and 30 parts by weight of natural rubber. Was kneaded in a compound kneader kneader at 100 to 120 ° C for about 12 minutes to prepare a compound.

The kneaded compound in the kneader was kneaded in an amount of 3 parts by weight of organic peroxide as a crosslinking agent to 100 parts by weight of the base material in a roll mill and uniformly mixed to prepare a sheet having a thickness of 2 mm. And is put into a mold having a thickness of 2 mm and press-molded under a press condition of 155 캜 and 170 kg / cm ² for about 5 minutes to prepare a gasket sheet.

Comparative Example  2

40 parts by weight of aramid fibers and 40 parts by weight of glass fibers were subjected to high-pressure air-opening treatment with 100 parts by weight of a base material composed of 80 parts by weight of acrylonitrile-butadiene rubber and 20 parts by weight of natural rubber, The mixture was kneaded at 100 to 120 ° C for about 12 minutes in a compound kneader kneader together with a composition composed of 100 parts by weight of the base material, 5 parts by weight of the metal oxide and 1 part by weight of the stearic acid to prepare the compound.

The kneaded compound in the kneader was kneaded in an amount of 3 parts by weight of organic peroxide as a cross-linking agent in 100 parts by weight of the base material in a roll mill, uniformly mixed and then made into a 2 mm-thick sheet, , And press-molded under a press condition of 170 kg / cm ² for about 5 minutes to prepare a gasket sheet.

Constituent Example Comparative Example One 2 One 2
Rubber Acrylonitrile butadiene ¹⁾ 70 80 70 80 Natural rubber ²⁾ 30 20 30 10 Zinc oxide ³⁾ 5 5 5 5 Stearic acid ⁴⁾ One One One One Kaolin ⁵⁾ 300 400 300 400 Aramid fiber ⁶⁾ 20 40 20 40 Glass fiber ⁷⁾ 40 40 40 40 Crosslinking agent ⁸⁾ 3 3 3 3 week)
1) NBR (oil resistance)
2) NR (natural rubber)
3) Zinc oxide (zinc oxide)
4) Stearic acid (stearic acid)
5) Kaolin (kaolin)
6) Aramid fiber (aramid fiber)
7) Glass fiber (glass fiber)
8) Trigonox (crosslinking agent)

The properties of the asbestos-free compositions prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were evaluated according to the following test and evaluation methods, and the results are shown in Table 2 below .

Evaluation items unit Example Comparative Example One 2 One 2 The tensile strength MPa 14 15 10 15 Processability - ○ ○ × ○ Dispersibility - ○ ○ × ○  Thickness uniformity ± mm 0.1 0.1 0.3 0.3

Processability: Good (Good), Fair (Fair), Good (Bad)

Dispersibility: Good (Good), Fair (Fair), Good (Bad)

1) Tensile strength: Measured using ASTM F152 method.

2) Processability: Roll processability of the composition

3) Dispersibility: Dispersion state of fiber and filler on sheet and gasket surface

4) Thickness uniformity: Thickness variation of sheet and gasket

As shown in Tables 1 and 2, in the case of the non-asbestos sheets and gaskets shown in Examples 1 and 2, unlike conventional non-asbestos sheets or gaskets, an excess amount of inorganic filler Despite the use of reinforcing fibers, the processability and dispersibility of the composition is good, and the uniformity of thickness (variation in thickness) can be seen to be stable within a tolerance of ± 0.1 mm.

However, in the case of Comparative Example 1, since the opening process of the reinforcing fibers as the production method of the present invention and the pretreatment process of mixing with the inorganic filler were not performed, the workability and dispersibility were poor, and the mechanical strength was lowered.

In addition, the thickness uniformity of the sheet and the gasket was inferior because the composition was not subjected to a sintering process during the formation of the sheet. In Comparative Example 2, the sheet was not subjected to a compaction step for ensuring the uniformity of the thickness of the sheet and gasket It was confirmed that the uniformity of the thickness of the sheet and the gasket was deteriorated.

The present invention has been proved to be superior in mechanical strength, processability and thickness uniformity through the above embodiments, but is not necessarily limited to the above configuration, and various substitutions, modifications, and alterations may be made without departing from the technical spirit of the present invention. This is possible.

Claims (2)

A first mixing step (S10) of mixing aramid fiber, glass fiber and kaolin in a dumbbell; A second mixing step (S20) of mixing the first composition of the first mixing step (S10) with acrylonitrile butadiene rubber, natural rubber, metal oxide, and stearic acid in a kneader; A third mixing step (S30) of mixing the second composition of the second mixing step (S20) and the crosslinking agent in a roll mill; And a sheet forming step (S40) of forming the third composition of the third mixing step (S30) into a sheet having a thickness of 1 to 2 mm, the method comprising the steps of:
In the first mixing step (S10), the aramid fiber and the glass fiber are subjected to a high-pressure air-opening treatment and mixed with kaolin, and the sheet surface is subjected to compaction at intervals of 1 to 10 mm in the sheet forming step (S40) Wherein the non-asbestos sheet is formed by a method comprising the steps of: A method for manufacturing an asbestos gasket, characterized in that the sheet produced in claim 1 is molded into a gasket in a high-temperature and high-pressure press.