JPH06287527A - Adhesive for use in molded carbon fiber heat-insulating material - Google Patents

Abstract

PURPOSE:To produce a specific adhesive to be used only in a small amt. to form a molded carbon fiber heat-insulating material hardly liable to delamination. CONSTITUTION:1 pt.wt. resin is blended with 0.5-1 pt.wt. solvent and 0.5-1 pt.wt. carbon filler to prepare an adhesive. Any resin can be used if it has a coking property and is soluble in a solvent and capable of carbonization through heating. For example, a phenol resin is pref. as the resin. Any solvent can be used if it can dissolve the resin. For example, an alcohol is pref. as the solvent. Any carbon filler can be used if it is neither deformed nor greatly changed in dimensions when heated, for example, at a temp. of at least 1,000 deg.C. Examples of the carbon filter include a carbon fiber powder having a diameter of at most, 20mum and a length of 10 to 50mum and a graphite powder having an average diameter of 30 to 70mum and contg. no particles of at least 200mum in size. These components are stirred and mixed together until the filler is maldistributed no more. It is better to prepare the adhesive every time when it is to be used. The amt. of the adhesive to be applied is 0.1 to 5g/cm<2>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive for carbon fiber molded heat insulating material, and more particularly to an adhesive for carbon fiber molded heat insulating material suitable for high temperature furnaces.

[0002]

2. Description of the Related Art Carbon fiber heat insulators are widely used as heat insulators for high temperature furnaces in ceramic sintering furnaces, semiconductor pulling furnaces, metal processing furnaces and the like. In particular, a carbon fiber molded heat insulating material obtained by impregnating a carbon fiber felt or a carbon fiber web with a thermosetting resin or the like, molding it into a plate shape, a cylindrical shape, etc., and then carbonizing it and graphitizing it has shape retention and is easy to handle. It has become the mainstream at present due to its advantages such as ease of use and less loss of carbon fiber powder.

However, since it is a molded product, it is difficult to manufacture a product having a complicated shape. On the other hand, the shape required for a carbon fiber heat insulating material, such as a heat insulating material for a semiconductor pulling furnace, tends to be complicated. One way to meet this requirement is to bond several pieces of carbon fiber insulation together with an adhesive to form the desired shape, and then heat-treat this to make a fully bonded unitary piece. , An adhesive for that has been proposed (Japanese Patent Publication Sho 56).
39353, Japanese Patent Laid-Open No. 300983). Also,
There are already commercial products from various companies as adhesives for carbon products (Ziguri "V-58a", Dainippon Ink and Chemicals "GC-HS").

[0004]

However, since each of the above-mentioned adhesives focuses on the adhesion of a flexible material such as carbon fiber felt or cloth or the adhesion of a dense graphite material, the carbon fiber molded thermal insulation is used. When applied to the material as it was, there were cases where inconvenience occurred. These adhesives include a resin or the like as an adhesive component, a carbon filler or the like for preventing the adhesive component from penetrating into the adherend and holding it at the adhesive interface, and for uniformly dispersing these and for adjusting the viscosity. Made of solvent etc.

An adhesive for the purpose of carbon fiber felt, cloth, etc. is a solvent for preventing the penetration of the adhesive solution into the adherend to keep the adherend flexible after adhering and for increasing the adhesive strength. Or the amount of carbon filler is increased. When such an adhesive is applied to a carbon fiber molded heat insulating material, since the adhesive solution hardly penetrates into the adherend, the adherend and the adhesive layer are almost completely independent phases. .

As a result, since the adhesive strength is inferior to that of the carbon fiber molded heat insulating material body, the adhesive layer may peel off with a slight strain. In a carbon fiber molded heat insulating material in which a given strain is propagated with almost no relaxation, the adhesive layer existing as an independent phase is easily peeled off. That is, it can be said that such an adhesive layer has poor toughness. This tendency is particularly remarkable when the surfaces of the carbon fiber molded heat insulating material where the fiber axial section is exposed are bonded.

On the other hand, the commercially available adhesives for carbon products are for adhering dense carbon materials to each other, and the carbon filler blended therein is an ultrafine powder of about 20 μm or less. When these adhesives are applied to the carbon fiber molded heat insulating material, the carbon fiber molded heat insulating material has a porosity of 70 to 95%.
Since the size of the void is about 10 to 200 μm, the adhesive is consumed to fill the void, and it is necessary to use a large amount of the adhesive to form the adhesive layer.

[0008]

Means for Solving the Problems The present inventors have found that if the amount of resin, solvent and carbon filler to be mixed in the adhesive is within a certain ratio range and the particle size of the carbon filler is within a certain range, the adhesive solution Does not sufficiently fill the voids, but slightly penetrates into the carbon fiber molded heat insulating material that is the adherend, and thus a tough adhesive layer that is composite with the carbon fiber molded heat insulating material that is the adherend is formed. The present invention has been completed by finding that it is difficult to peel off when formed.

That is, the present invention uses 0.5 to 1 part by weight of a solvent and 0.5 to 1 part by weight of a carbon filler for 1 part by weight of a resin component.
It exists in an adhesive for a carbon fiber molded heat insulating material mixed with 1 part by weight. The present invention will be described in detail below. The resin used in the present invention is caking, is soluble in a solvent, and is not limited as long as it is carbonized by heating, but usually a phenol resin, a furan resin or the like is used. It can be preferably used.

The solvent is not limited as long as it can dissolve the resin, but alcohols, ketones and the like, particularly alcohols such as methanol, ethanol and propyl alcohol can be preferably used. The carbon filler is not particularly limited as long as the shape does not change when heated to 1000 ° C. or more and the dimensions do not change significantly, but carbon filler, artificial or natural carbon is particularly suitable for the purpose of the present invention. Graphite powder.

When carbon fiber powder is used as the carbon filler, the fiber diameter is 20 μm or less and the length is 10 to 50.
It is preferably in the range of μm. If the diameter and the length are out of this range, it becomes difficult to penetrate into the carbon fiber molded heat insulating material, which may hinder the formation of the adhesive layer combined with the carbon fiber molded heat insulating material. On the other hand, when the amount exceeds the upper limit, it becomes difficult to uniformly disperse the adhesive in the adhesive and the coatability may be deteriorated.

There is no particular limitation on the type of carbon fiber, PAN
Any of a system, a pitch system, a phenol resin system and the like can be preferably used. On the other hand, when graphite powder is used as the carbon filler, the average particle size is 30 to 70 μm,
It is preferable not to include particles having a particle size of m or more. If the amount is out of this range, the formation of the composite adhesive layer is hindered, and the dispersibility and the coating property are likely to have a problem, as in the case of using carbon fiber powder as the filler.

The desired adhesive for carbon fiber molded heat insulating material can be obtained by stirring and mixing the above components until the uneven distribution of the filler is eliminated. In order to prevent the composition from changing or deteriorating, it is preferable to prepare a necessary amount each time it is used, or to store it in a cool dark place such as in a freezer after sealing after sealing. The carbon fiber molded heat insulating material is adhered to the adhering surfaces of both pieces to be adhered by brushing, roller coating, spatula coating or the like in an amount of 0.1 to 5 g.
/ Cm < ² >, preferably 0.5 to ² g / cm < ² > is applied, and the adhesive surfaces are abutted and fixed.

The fixing is carried out by using a metal pin, a graphite pin or the like, or by applying a load, and in this state, it is heated at 120 to 300 ° C. for 10 to 300 minutes to thermally cure the resin component. As a result, a certain amount of strength is expressed and the adhesion is maintained, so the pins used for fixing are removed or the load is removed, and then in an inert atmosphere,
Heat to above 00 ° C. By this treatment, the adhesive is completely converted into carbonaceous material and exhibits the maximum adhesive strength.

[0015]

【Example】

(Example 1) 1 part by weight of resol type phenol resin "PL-2211" (resin content 60%, solvent = 40% methanol) manufactured by Gunei Chemical Co., Ltd. was added to carbon fiber "Dilead" manufactured by Mitsubishi Kasei Co., Ltd. 0.45 part by weight of (fiber diameter 11 μm) crushed to an average length of 24 μm was added and sufficiently stirred to obtain an adhesive.

This adhesive was cut into 125 × 75 × 40 mm carbon fiber molded heat insulating and insulating material “Carbolite” manufactured by Mitsubishi Kasei Co., Ltd. (specific gravity 0.2 g / cm ³ , porosity 91%).
Of 2 g / on the surface of 75 × 40 mm where the fiber axis section is exposed
It was evenly applied at a rate of cm ² , and two pieces of this were butt-bonded to each other to give a size of 250 × 75 × 40 mm. Next, heat the resin surface by heating for 20 minutes at 140 ° C. with a load applied to the adhesive surface, and then 1000 in a nitrogen atmosphere.
A test piece for measuring the adhesive strength was obtained by heating to ° C.

After a total of four portions of 15 mm from both ends of this test piece and 15 mm on both sides of the adhesive portion were wound and fastened with adhesive tape to prevent interlayer shearing of the heat insulating material,
Three-point bending was performed at a distance between spans of 200 mm and a displacement speed of 10 mm / min (the adhesive layer portion serves as a displacement addition point). Since the destruction is caused by the peeling of the adhesive surface, the maximum load at the time of destruction is the adhesive area (40 × 75 = 3000 mm ² =
It was divided by 30 cm ² ) to obtain the adhesive strength. The adhesive used in this example is an average of 6 test pieces of 13.3 kg / cm.
A value of ² was shown, and the peeling of the adhesive surface was caused by pulling out the fiber lumps in the heat insulating material of each other.

(Comparative Example 1) 1 part by weight of a resol type phenolic resin "PL-2211" manufactured by Gunei Chemical Co., Ltd. was crushed with carbon fiber "Dilead" manufactured by Mitsubishi Kasei Co., Ltd. to an average length of 72 μm. An adhesive was obtained by adding 0.45 parts by weight and stirring sufficiently. Using this adhesive, the same test piece for measuring adhesive strength as in Example 1 was prepared and the adhesive strength was measured. The adhesive strength of this adhesive is 6.1 kg / on average for 6 test pieces.
The value of cm ^{2 was obtained} , and the peeling of the adhesive surface had a part in which the fiber lumps in the heat insulating material were pulled out, but in most cases the interface between the adhesive layer and the heat insulating material peeled off cleanly. Was there.

(Comparative Example 2) 1 part by weight of resol type phenolic resin "PL-2211" manufactured by Gunei Chemical Co., Ltd. was crushed with carbon fiber "Dilead" manufactured by Mitsubishi Kasei Co., Ltd. to an average length of 24 .mu.m. An adhesive was obtained by adding 9 parts by weight and stirring sufficiently. Using this adhesive, the same test piece for measuring the adhesive strength as in Example 1 was prepared, but it was extremely difficult to make a uniform coating film because the carbon fiber powder mixed in the adhesive was lumpy. Met. The adhesive strength of this adhesive was an average of 4.8 kg / cm ² of the 6 test pieces, and the peeling of the adhesive surface occurred in the form where the interface between the adhesive layer and the heat insulating material was neatly peeled off. .

[0020]

EFFECT OF THE INVENTION By using the adhesive for carbon fiber molded heat insulating material of the present invention, a carbon fiber molded heat insulating material which is less likely to peel off can be obtained, and the amount thereof used can be small.

Claims (3)

[Claims] 1. An adhesive for a carbon fiber molded heat insulating material comprising a resin, a solvent and a carbon filler, the compounding ratio of which is 0.5 to 1.0 of solvent and 0.5 of carbon filler to resin 1 by weight ratio. An adhesive compounded in the range of 1.0. 2. A carbon filler having a diameter of 20 μm or less and a length of 1
The adhesive according to claim 1, which is a carbon fiber powder of 0 to 50 µm. 3. The carbon filler has an average particle size of 30 to 70 μm.
The adhesive according to claim 1, which is graphite powder that does not include particles having a particle size of 200 μm or more.