JP3411495B2 - Cryogenic insulation and epoxy adhesive - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic insulating material and an epoxy adhesive which are excellent in insulation and adhesiveness even at cryogenic temperatures.

[0002]

2. Description of the Related Art In order to secure and maintain a superconducting state at an extremely low temperature such as when using a superconducting coil, the insulation capacity such as the dielectric breakdown voltage of the insulating material is important. The adhesion state between the insulating material and the conductor is particularly important.

A glass fiber reinforced composite material composed of glass fiber and epoxy resin is often used as a material for the insulating material. When the glass fiber reinforced composite material is cooled to an extremely low temperature, cracks occur in the resin portion. As a result, the phenomenon that the glass fiber reinforced composite material peels off occurs. Then, when the glass fiber reinforced composite material is peeled off, the superconducting material can be easily moved, the superconducting material vibrates and generates heat, and a phenomenon (so-called quench phenomenon) occurs in which the superconducting state is broken by the temperature rise accompanying this vibration. There is a problem that it ends up.

On the other hand, as a high-performance insulating material, a highly reliable polyimide resin film showing a breakdown voltage about 10 times or more as compared with a general insulating material such as a glass fiber reinforced composite material is used. There is. However, this polyimide resin film has the drawback of poor adhesion.

Therefore, when joining a polyimide resin film and a conductive material, for example, or when joining a polyimide resin film through a glass cloth, a resin having a relatively high adhesive force such as an epoxy resin is used as an adhesive. By doing so, the poor adhesiveness is compensated.

However, even with the above-mentioned structure, distortion occurs due to the difference in the heat shrinkage ratio between the respective constituent materials in the extremely low temperature region, and the adhesive force becomes insufficient (it should be noted that good adhesion occurs in the normal temperature region). Be done.).

The present invention solves the above problems,
(EN) Provided are an cryogenic insulating material and an epoxy adhesive which can effectively exhibit the high insulating properties of a polyimide resin film even under cryogenic conditions.

[0008]

[Means for Solving the Problems] Inorganic base material and polyimide resin film are combined with epoxy resin and polyvinyl formal.
Resin, phenoxy resin or carboxylated NBR
The present invention relates to a cryogenic insulating material, characterized in that it is provided through an epoxy resin composition containing 5% (by weight) or more of aluminum.

Further, the inorganic substrate, polyvinyl epoxy resin
Nylformal resin, phenoxy resin or carboxy
A cryogenic insulating material comprising a polyimide resin film bonded to an inorganic base material prepreg impregnated with an epoxy resin composition containing 5% (weight) or more of silylated NBR rubber. is there.

Further, the glass base material and the polyimide resin film are replaced with epoxy resin, polyvinyl formal resin, and fluorine resin.
5% of enoxy resin or carboxylated NBR rubber
(Weight) The present invention relates to a cryogenic insulating material, characterized in that the insulating material is attached through an epoxy resin composition mixed therein.

In addition, the glass substrate, epoxy resin and poly
Vinyl formal resin, phenoxy resin or carbo
A cryogenic insulating material comprising a glass base material prepreg impregnated with an epoxy resin composition containing 5% (by weight) or more of a xylated NBR rubber , and a polyimide resin film attached thereto. is there.

Further, the glass cloth and the polyimide resin film are combined with epoxy resin, polyvinyl formal resin,
Phenoxy resin or carboxylated NBR rubber 5
The present invention relates to a cryogenic insulating material, characterized in that the insulating material is attached through an epoxy resin composition mixed in an amount of (%) by weight or more.

[0013] In addition, the glass cloth, Po in the epoxy resin
Livinylformal resin, phenoxy resin or cal
A cryogenic insulating material comprising a glass cloth prepreg impregnated with an epoxy resin composition containing 5% (weight) or more of a boxylated NBR rubber , and a polyimide resin film bonded to the glass cloth prepreg. .

Further, a glass cloth and a polyimide resin film having a tensile elongation of 80 to 160% at room temperature are used as an epoxy resin, a polyvinyl formal resin and a phenoxy resin.
Alternatively, the present invention relates to a cryogenic insulating material, characterized in that it is additionally provided through an epoxy resin composition containing 5% (weight) or more of carboxylated NBR rubber .

[0015] In addition, the glass cloth, Po in the epoxy resin
Livinylformal resin, phenoxy resin or cal
A glass cloth prepreg impregnated with an epoxy resin composition containing 5% (by weight) or more of boxylated NBR rubber, and a polyimide resin film having a tensile elongation of 80 to 160% at room temperature, which is bonded to the glass cloth prepreg. It relates to a cryogenic insulating material.

Further, a glass cloth and a polyimide resin film having the following structure are used as an epoxy resin in a polyvinyl chloride resin.
Leformal resin, phenoxy resin or carboxy
The present invention relates to a cryogenic insulating material, characterized in that it is attached via an epoxy resin composition in which 5% (by weight) or more of rubberized NBR rubber is mixed.

[0017]

[Chemical 1]

Further, a glass cloth prepreg obtained by impregnating a glass cloth with an epoxy resin composition obtained by mixing 5% (weight) or more of a polymer having a number average molecular weight of 10,000 or more in an epoxy resin, a polyimide resin having the following structure The present invention relates to a cryogenic insulating material characterized by being formed by laminating films together.

[0019]

[Chemical 1]

The cryogenic insulating material according to any one of claims 1 to 10, wherein the epoxy resin composition is mixed with the insulating material in an amount of 30 to 60% (by weight). The present invention relates to a cryogenic insulating material.

[0021]

The epoxy resin is mixed with polyvinyl formal resin, phenoxy resin, or carboxylated NBR rubber in an amount of 5% (by weight) or more, and has a stronger adhesive force under cryogenic conditions than before the polymer is mixed. The present invention relates to an epoxy-based adhesive characterized by the above.

[0023]

The function and effect of the present invention are summarized as the claims, the effects obtained by repeated experiments.

Glass cloth and polyimide resin film are used as epoxy resin, polyvinyl formal resin, and phenoxy resin.
A cryogenic insulating material provided through an epoxy resin composition containing 5% or more of a resin or carboxylated NBR rubber is excellent even under cryogenic conditions such as when used as an insulating material for a superconducting coil. It exhibits excellent adhesive strength and insulating power, and does not cause peeling or cracking of the cryogenic insulating material.

Since the present invention is constituted as described above, it has sufficient adhesiveness even under extremely low temperature conditions and is capable of effectively exhibiting the high insulating property of the polyimide resin film. It becomes an insulating material and an epoxy adhesive.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings show an example of a specific embodiment of the present invention.

1 and 2 show a superconducting coil 2 formed by winding a superconducting material 1 and an inner wall 5 of a cooling unit 3 for cooling the superconducting coil 2 provided with cryogenic insulating materials 4a and 4b. is there.

Further, the cooling section 3 is provided with a cooling pipe 6 which allows a coolant such as liquid helium for cooling the cooling section 3 to pass therethrough.

The method of disposing the cryogenic insulating materials 4a and 4b will be described in detail.

Cryogenic insulating material 4a disposed on the superconducting material 1.
First, the epoxy resin containing PBH (that is,
Epoxy resin composition. ) Is impregnated into a glass cloth to form a glass cloth prepreg, and a polyimide resin film is attached to the glass cloth prepreg to form a prepreg-like cryogenic insulating material.

Subsequently, a prepreg-shaped cryogenic insulating material is spirally wound around the superconducting material 1 to form a prepreg-shaped insulating layer on the superconducting material 1.

On the other hand, as the cryogenic insulating material 4b to be arranged on the inner wall 5 of the cooling section 3, first, a glass cloth is impregnated with an epoxy resin (that is, an epoxy resin composition) to which PBH is added (glass epoxy prepreg). Then, a polyimide resin film is attached to the glass cloth prepreg, and a glass cloth prepreg is further attached to the polyimide resin film to form a prepreg-shaped cryogenic insulating material.

Subsequently, a prepreg-shaped cryogenic insulating material is arranged on the inner wall 5 of the cooling unit 3 like a wallpaper, and a prepreg-shaped insulating layer is formed on the inner wall 5 of the cooling unit 3.

The prepreg-shaped insulating layer thus arranged is cured by heating, and the cryogenic insulating materials 4a and 4b are integrally arranged in the gap between the superconducting material 1 and the cooling part 3.

Since this embodiment is constructed as described above, no peeling or cracking occurs in the cryogenic insulating materials 4a and 4b arranged in the gap between the superconducting material 1 and the cooling part 3, and the superconducting coil is quenched. The insulating material for cryogenic use has excellent practicality and does not cause a phenomenon.

[0036]

EXAMPLES Hereinafter, experimental examples that support the effects of the present invention will be described.

The polyimide resin film is a polyimide resin film having a tensile elongation of 80 to 160% at room temperature, which is manufactured by Ube Industries, Ltd. UPILEX R (see the following chemical formula 1. Average tensile elongation at room temperature of 130%. Hereinafter, UPI).
It is called LEX R. ) Is used for comparison and has an average tensile elongation of 30% at normal temperature manufactured by Ube Industries, Ltd.
EX S (see Chemical Formula 2 below; hereinafter referred to as UPILEX S) and KAPTON H manufactured by DuPont Co., Ltd. having an average tensile elongation of 70% at room temperature (see Chemical Formula 3 below; hereinafter, K
Called APTON H. ) Is used.

[0038]

[Chemical 1]

[0039]

[Chemical 2]

[0040]

[Chemical 3]

Further, a polymer having a number average molecular weight of 10,000 or more is a polyvinyl formal resin, Vinylec E manufactured by Chisso Corporation (see the following chemical formula 4. The polyvinyl formal resin has a number average molecular weight of about 1,000,000. Hereinafter referred to as PBH). , YP manufactured by Tohto Kasei Co., Ltd. as a phenoxy resin
-50 (see Chemical Formula 5 below, number average molecular weight 58600, hereinafter referred to as phenoxy resin), and carboxylated N.
Nippon Rubber 107 manufactured by Nippon Zeon Co., Ltd. as BR rubber
2 (See Chemical Formula 6 below. Carboxyl-modified acrylonitrile / butadiene copolymer having a number average molecular weight of about 300,000.
It is called NBR rubber. ) Is used.

[0042]

[Chemical 4]

[0043]

[Chemical 5]

Note that n indicates repetition, and generally n = 1.
00 or more, about 200 on average.

[0045]

[Chemical 6]

In the above chemical formula, the symbols n, X, Y,
Z, x, y, and z each represent a natural number. The symbols described except for n indicate the mixing ratio of structural formulas enclosed by square brackets.

The mixing ratio of the symbols X, Y and Z in the chemical formula 4 is
In general:

X = 78% or more Y = 4.5 to 8.5% Z = 9 to 13% The mixing ratio of the symbols x, y and z in the chemical formula 6 is generally as follows.

X = 1 to 40% or more y = 52-98% z = 1 to 8%.

The measuring conditions of the adhesive force are JIS K 6
According to 850. The adherend is SUS304, and the shear fracture force between the adherend and the insulating material is the adhesive force. However, the temperature condition is the liquid nitrogen temperature (about 77 K or less). In addition, the withstand voltage measurement conditions are JIS K 6911.
According to.

<Experimental Example 1> In order to investigate the relationship between the resin content of the epoxy resin composition and the adhesive strength, an epoxy resin containing a polymer (that is, an epoxy resin composition) was used while changing the resin content. A glass cloth was impregnated to form a glass cloth prepreg, and the adhesive strength and withstand voltage of this glass cloth prepreg were measured.
The thickness of the glass cloth prepreg is 50 μm, and the polymer used is PBH.

[0052]

[Table 1]

Thus, the glass cloth prepreg having a resin content of 20 to 60% (by weight) has an adhesive force of 30MP.
The result was a or more, and good adhesion was exhibited. The withstand voltage is lower than that in the case where the polyimide resin film is used.

<Experimental Example 2> In order to investigate the relationship between the addition ratio of the polymer in the epoxy resin composition and the adhesive force, the epoxy resin containing the polymer (that is, the epoxy resin composition) was added with the polymer addition rate. Was changed to impregnate a glass cloth to form a glass cloth prepreg, and the adhesive strength and withstand voltage of the glass cloth prepreg were measured. The thickness of the glass cloth prepreg is 5
At 0 μm, the polymer used is PBH.

[0055]

[Table 2]

Thus, the polymer addition rate is 5 to 35%.
Adhesive strength of epoxy resin composition (weight) 30MP
The result was a or more, and good adhesion was exhibited. When the polymer addition rate is 40% (weight), the glass cloth cannot be impregnated with the polymer, and the glass cloth prepreg cannot be formed.

<Experimental Example 3> In order to examine the relationship between the resin content and the adhesive force of an insulating material having a film-glass cloth laminated structure of glass cloth and a polyimide resin film, an epoxy resin containing a polymer (ie, , Epoxy resin composition) is impregnated into a glass cloth by changing the resin content to form a glass cloth prepreg, and the glass cloth prepreg is subjected to UPI.
LEX R was stuck together to form an insulating material, and the adhesive strength and withstand voltage of this insulating material were measured. The glass cloth has a thickness of 30 μm and the polyimide resin film has a thickness of 25 μm.
In m, the polymer used is PBH.

[0058]

[Table 3]

Thus, the glass cloth prepreg having a resin content of 20 to 60% (by weight) has an adhesive force of 30MP.
The result was a or more, and good adhesion was exhibited. Further, the withstand voltage was about four times that of Experimental Example 1, and the withstand voltage was good.

<Experimental Example 4> In order to investigate the relationship between the polymer addition rate and the adhesive force of an insulating material having a glass-cloth and polyimide resin film laminated film-glass cloth structure, a polymer-added epoxy resin ( That is, the epoxy resin composition.) Is impregnated into a glass cloth by changing the polymer addition rate to form a glass cloth prepreg, and the glass cloth prepreg is U-coated.
PILEX R was bonded to form an insulating material, and the adhesive force and withstand voltage of this insulating material were measured. The glass cloth has a thickness of 30 μm and the polyimide resin film has a thickness of 2 μm.
At 5 μm, the polymer used is PBH.

[0061]

[Table 4]

Thus, the polymer addition rate is 10 to 35%.
Adhesive strength of epoxy resin composition (weight) 30MP
The result was a or more, and good adhesion was exhibited. Moreover, the withstand voltage was about four times that of Example 1, and the withstand voltage was good. The polymer addition rate is 40% (weight)
In that case, the prepreg cannot be formed as in Experimental Example 2.

<Experimental Example 5> In order to examine the changes in the adhesive force and the withstand voltage depending on the polymer used in Experimental Example 4, the adhesive force and the resistance of the insulating material in which phenoxy resin and NBR rubber were added instead of PBH as the polymer. The voltage was measured. The conditions other than the polymer used were the same as in Experimental Example 4.

[0064]

[Table 5]

As described above, the insulating material to which the phenoxy resin was added showed the same adhesive strength and withstand voltage as PBH.
The adhesive strength of the insulating material containing BR rubber is 30% of polymer addition.
% (Weight) was 30 MPa or less, which was insufficient. Therefore, it was proved that the NBR rubber cannot obtain the adhesive strength as much as PBH and phenoxy resin.

This is because the elasticity of the adhesive is remarkably reduced at extremely low temperatures, stress such as shrinkage difference between the adhesive and the adhesive cannot be relieved, and cracks or peeling occur at the adhesive or the adhesive interface. And the like, and PBH
Since the molecular structure of phenoxy resin and phenoxy resin is a structure that easily expands and contracts compared to the molecular structure of NBR rubber, PBH and phenoxy resin have higher elasticity than NBR rubber at extremely low temperatures, and the elasticity of epoxy resin decreases. It is speculated that it may be easier to supplement

<Experimental Example 6> In order to examine the changes in the adhesive strength and withstand voltage of the insulating material depending on the thickness of the polyimide resin film and the glass cloth, the resin content and the polymer addition rate were set constant, and the polyimide resin film The adhesive strength and the withstand voltage of the insulating material having the film-glass cloth laminated structure in which the thickness and the thickness of the glass cloth prepreg were changed were measured. The polymer used was P
The polymer addition rate of BH is 30% (weight), and the resin content of the epoxy resin is 40% (weight).

[0068]

[Table 6]

Thus, it was confirmed that even if the thickness of the polyimide resin film and the glass cloth changes, the adhesive force of the insulating material is hardly affected.

It should be noted that as the thickness of the glass cloth increases, the withstand voltage decreases because the glass cloth laminate has a lower withstand voltage than the polyimide resin film. This is because it will end up. Therefore, when a polyimide resin film is attached to a thin glass cloth, the insulating material has a high withstand voltage even if it is thin.

<Experimental Example 7> In order to examine changes in the adhesive strength and withstand voltage of the insulating material due to the elongation of the polyimide resin, a polyimide resin film U
The adhesive strength and the withstand voltage of the insulating material of the film-glass cloth bonding structure using PILEX S and KAPTON H were measured. The thickness of the glass cloth is 30 μm
Is.

[0072]

[Table 7]

As described above, the insulating material using the polyimide resin film having a low elongation has a lower adhesive strength than the insulating material using the polyimide resin film having a high elongation.
In addition, in UPIREX S having a lower elongation, the adhesive strength was 30 MPa or less, which was insufficient regardless of the resin content and the polymer addition rate.

This is similar to Experimental Example 5 in that UPILEX
R is higher in elongation than UPILEX S and KAPTON H, and it is speculated that UPILEX R itself can relieve a part of the stress even if the elasticity of the epoxy resin is lowered under cryogenic conditions. It

<Experimental Example 8> In order to investigate the relationship between the resin content and the adhesive force of an insulating material having a glass cloth-film-glass cloth bonding structure in which two glass cloth prepregs and a polyimide resin film are bonded, a polymer was used. A glass cloth prepreg is formed by impregnating a glass cloth with an epoxy resin added with (i.e., an epoxy resin composition) and changing the resin content, and a polyimide resin film is attached to the glass cloth prepreg. The adhesive strength and the withstand voltage of the insulating material in which the glass cloth prepreg was laminated on the film were measured. The thickness of the glass cloth is 50 μm × 2 =
100 μm, polyimide resin film thickness is 25 μm
The polymer used was PBH.

[0076]

[Table 8]

As described above, the adhesive strength of the insulating material having a resin content of 30 to 60% (by weight) was 30 MPa or more, and good adhesive strength was exhibited. Further, the withstand voltage was about three times that of Experimental Example 1, and the withstand voltage was good.

<Experimental Example 9> In order to investigate the relationship between the polymer addition rate and the adhesive force of the insulating material having a glass cloth-film-glass cloth bonding structure in which two glass cloth prepregs and a polyimide resin film are bonded, A glass cloth prepreg is formed by impregnating a glass cloth with a molecule-added epoxy resin (that is, an epoxy resin composition) while changing the polymer addition rate.
A polyimide resin film was attached to the glass cloth prepreg, and the adhesive strength and withstand voltage of the insulating material obtained by attaching the glass cloth prepreg onto the polyimide resin film were measured. The glass cloth prepreg has a thickness of 50 μm × 2 = 100 μm, the polyimide resin film has a thickness of 25 μm, and the polymer used is PBH.

[0079]

[Table 9]

Thus, the polymer addition rate is 10 to 30%.
In the insulating material using the (weight) epoxy resin composition, the adhesive force was 30 MPa or more, and good adhesive force was exhibited. Also, in terms of withstand voltage, it is about 3 compared with Experimental Example 1.
The value was doubled and the withstand voltage was good. When the polymer addition rate is 40% (weight), the prepreg cannot be formed as in Experimental Examples 2 and 4.

<Experimental Example 10> In order to examine the changes in the adhesive strength and the withstand voltage depending on the polymer used in Experimental Example 9, the adhesive strength and the resistance of an insulating material to which a phenoxy resin and an NBR rubber were added instead of PBH as the polymer. The voltage was measured. The conditions other than the polymer used were the same as in Experimental Example 9.

[0082]

[Table 10]

As described above, the insulating material to which the phenoxy resin was added showed the same adhesive strength and withstand voltage as PBH, but N
The adhesive strength of the insulating material containing BR rubber was slightly lower than that of PBH and phenoxy resin, although there was no problem in practical use.

Similar to Experimental Example 5, the elasticity of the adhesive was remarkably reduced at extremely low temperatures, and stress such as displacement due to the difference in shrinkage between the adhesive and the adhesive could not be alleviated. Since it causes cracks or peeling at the adhesive or the adhesive interface, and the molecular structure of PBH or phenoxy resin is a structure that easily expands and contracts as compared with the molecular structure of NBR rubber, PBH at extremely low temperatures. It is speculated that the phenoxy resin and the phenoxy resin have higher elasticity than the NBR rubber and may more easily compensate for the decrease in elasticity of the epoxy resin.

<Experimental Example 11> The adhesive force of the insulating material depending on the thickness of the polyimide resin film and the glass cloth of the insulating material having the glass cloth-film-glass cloth bonding structure of two glass cloth prepregs and the polyimide resin film. In order to investigate the change in withstand voltage, the resin content rate and the polymer addition rate were set to be constant, and the adhesive force and withstand voltage of the insulating material in which the thickness of the polyimide resin film and the glass cloth were changed were measured. The glass cloth had a thickness of two sheets, the polymer used was PBH, the polymer addition rate was 30% (by weight), and the resin content of the epoxy resin was 40%. (weight)
Is.

[0086]

[Table 11]

As described above, it was confirmed that even if the thickness of the polyimide resin film and the glass cloth was changed, the adhesive force of the insulating material was hardly affected. As with Experimental Example 6, as the glass cloth becomes thicker, the withstand voltage decreases.

<Experimental Example 12> Two glass cloth prepregs and a polyimide resin film are laminated together to form a glass cloth-film-glass cloth structure. UPILEX S and KA as a polyimide resin film to investigate the change of
The adhesive strength and withstand voltage of the insulating material using PTON H were measured. The thickness of the glass cloth is 50 μm × 2 = 10
It is 0 μm.

[0089]

[Table 12]

Thus, UPILEX S with low elongation
Insulation materials using KAPTON H and U have high elongation
The adhesive strength was lower than that of the insulating material using PILEX R. In UPILEX S having a lower elongation, the adhesive force was 30 MPa or less, which was insufficient regardless of the resin content and the polymer addition rate.

<Experimental Example 13> A polyimide resin film having poor adhesion to a conductive material was impregnated with an epoxy resin composition containing a polymer to obtain a prepreg, and the adhesive strength and withstand voltage were measured. UPILEX R was used as the polyimide resin film, and the thickness of the polyimide resin film was set to 50 μm.

[0092]

[Table 13]

Thus, the polymer addition rate is 30% (weight)
In addition, when the resin content was 5 to 30% (by weight), the adhesive strength of the polyimide resin film prepreg was 30 MPa or more, and good adhesive strength was exhibited. The withstand voltage was about 10 times that of glass cloth. The result of the above experimental example is UPILEX, which has high elongation as a polyimide resin film.
When R is used and an epoxy resin having originally strong adhesiveness is used as an adhesive, and when the epoxy resin contains a polymer having a large molecular weight and high elasticity, it has excellent adhesiveness even under extremely low temperature conditions. It suggests that it will be an insulating material.

Summarizing the results of the above experimental examples, for cryogenic use, a glass cloth and a polyimide resin film are attached through an epoxy resin composition containing 5% (weight) or more of a polymer having a number average molecular weight of 10,000 or more. The insulation is
It has good adhesion and insulation even under extremely low temperature conditions.

When a polyimide resin film having a tensile elongation of 80 to 160% at room temperature is used as the polyimide resin film, the adhesive strength is further enhanced.

When a polymer having high elasticity at extremely low temperature (polyvinyl formal resin or phenoxy resin) is used as the polymer, the adhesive force is further enhanced. However, even if a carboxylated NBR rubber having a slightly poor stretchability is used, there is no problem in practicality.

When the epoxy resin composition is mixed in an amount of 30 to 60% (weight) with respect to the insulating material, the adhesive strength is further increased.

The epoxy resin composition satisfying the above conditions can impart high adhesive force even to a polyimide resin film having low adhesive force.

[Brief description of drawings]

FIG. 1 is an explanatory perspective view of the present embodiment.

FIG. 2 is an explanatory sectional view of the present embodiment.

[Explanation of symbols]

None

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H01B 13/00 561 H01B 13/00 561Z 17/60 17/60 L (58) Fields investigated (Int.Cl. ⁷ , DB name) ) H01B 3/30 H01B 3/40 H01B 13/00 561 H01B 17/60 B32B 27/00 B32B 27/38

Claims (12)

(57) [Claims] 1. An inorganic base material and a polyimide resin film are attached via an epoxy resin composition in which a polyvinyl formal resin, a phenoxy resin or a carboxylated NBR rubber is mixed in an epoxy resin in an amount of 5% (by weight) or more. Insulating material for cryogenic use. 2. An inorganic base material prepreg obtained by impregnating an inorganic base material with an epoxy resin composition in which an epoxy resin is mixed with polyvinyl formal resin, phenoxy resin or carboxylated NBR rubber in an amount of 5% (by weight) or more, a polyimide resin. A cryogenic insulating material, which is formed by laminating films. 3. A glass base material and a polyimide resin film are attached via an epoxy resin composition in which a polyvinyl formal resin, a phenoxy resin or a carboxylated NBR rubber is mixed in an epoxy resin in an amount of 5% (by weight) or more. Insulating material for cryogenic use. 4. A glass base material prepreg obtained by impregnating a glass base material with an epoxy resin composition in which an epoxy resin is mixed with polyvinyl formal resin, phenoxy resin or carboxylated NBR rubber in an amount of 5% (by weight) or more, a polyimide resin. A cryogenic insulating material, which is formed by laminating films. 5. A glass cloth and a polyimide resin film, an epoxy resin containing polyvinyl formal resin, a phenoxy resin, or a carboxylated NBR rubber in an amount of 5%.
(Weight) An insulating material for cryogenic temperatures, characterized by being provided through an epoxy resin composition mixed as above. 6. A polyimide resin film is applied to a glass cloth prepreg obtained by impregnating a glass cloth with an epoxy resin composition in which an epoxy resin is mixed with polyvinyl formal resin, phenoxy resin or carboxylated NBR rubber in an amount of 5% (by weight) or more. A cryogenic insulating material characterized by being bonded together. 7. A glass cloth and a tensile elongation at room temperature of 8
A polyimide resin film of 0 to 160% is attached via an epoxy resin composition in which a polyvinyl formal resin, a phenoxy resin or a carboxylated NBR rubber is mixed in an epoxy resin in an amount of 5% (by weight) or more. Cryogenic insulation. 8. A glass cloth prepreg obtained by impregnating a glass cloth with an epoxy resin composition in which 5% (weight) or more of a polyvinyl formal resin, a phenoxy resin, or a carboxylated NBR rubber is mixed with an epoxy resin is stretched at room temperature. An insulating material for cryogenic temperatures, which is formed by laminating a polyimide resin film having a degree of 80 to 160%. 9. A glass cloth and a polyimide resin film having the following structure are attached via an epoxy resin composition in which 5% (weight) or more of polyvinyl formal resin, phenoxy resin or carboxylated NBR rubber is mixed in epoxy resin. Cryogenic insulation material characterized by [Chemical 1] 10. A polyimide resin having the following structure in a glass cloth prepreg obtained by impregnating a glass cloth with an epoxy resin composition prepared by mixing 5% (weight) or more of a polymer having a number average molecular weight of 10,000 or more in an epoxy resin. A cryogenic insulating material, which is formed by laminating films. [Chemical 1] 11. The cryogenic insulating material according to claim 1, wherein the epoxy resin composition is mixed in an amount of 30 to 60% (weight) with respect to the insulating material. Insulating material for cryogenic use. 12. Epoxy resin mixed with polyvinyl formal resin, phenoxy resin, or carboxylated NBR rubber in an amount of 5% (by weight) or more, and having a stronger adhesive force under cryogenic conditions than before the polymer is mixed. An epoxy adhesive characterized in that.