JP3442008B2 - Self-extinguishing flame retardant sheet - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant sheet used in a radioactive material handling office. Specifically, halogen-free gas, NO ₂ gas, SO ₂ gas, etc. are not generated during flame-retardant, and phosphorus-based gas that causes clogging of a filter through which combustion gas passes is not generated, and the residual amount of ash is very small. so,
The present invention relates to a flame-retardant sheet used for covering the floor surface, equipment, material storage area, wall surface, etc., of a radioactive material handling site that is easy to handle.

[0002]

2. Description of the Related Art Conventionally, as a method of making a flammable synthetic resin such as a polyolefin resin flame-retardant, a method of using a halogen compound and antimony trioxide in combination is well known. Further, a flame-retardant composition prepared by blending an organopolysiloxane and an organometallic compound without blending a chlorine-based additive with a flammable non-chlorine polymer so as not to generate a toxic gas during incineration. It is known. This composition is problematic because it emits chlorine, NO ₂ or SO ₂ , and produces a large amount of ash when incinerated. In addition, JP-A-3
No. 7767, JP-A-3-15539, JP-A-4-332640, and JP-A-164594 describe compositions and films using urea as a flame retardant. Strong polarity and poor compatibility with thermoplastic polymers. Urea has a high solubility in water,
It has a high hygroscopic property and easily aggregates, resulting in poor handleability. Further, it has a defect that it melts at 132 ° C. and decomposes.

[0003]

In particular, in areas where radioactive materials are handled, such as nuclear power plants and radioactive material research laboratories, a synthetic resin film is used to prevent radioactive materials from adhering to floors, walls, ceilings, partitions and the like. However, after a certain period of time, the old film is replaced with a new film and the removed old film is incinerated. However, since the residual ash content remains radioactive after incineration, increasing the ash content increases the material cost and storage space required to seal the radioactive ash content, so it is required that the residual ash content after incineration be low. It At the same time, the strength is required so that the floor or the like will not be exposed due to damage during use. In recent years, not only halogen-containing substances but also phosphorus-containing substances have not been used as flame retardants. The present invention is to solve the above problems, it is possible incineration yet flame retardancy, is then when the incineration less occurrence of ash without generating harmful gases, strength provides a strong composite film The purpose is to

[0004]

Means for Solving the Problems The present invention is selected from "1. A polyolefin resin aqueous dispersion having a resin solid content of 30 to 75% by weight and a polyurethane resin aqueous dispersion having a resin solid content of 25 to 70% by weight. For 1 or 2 or more resin aqueous dispersions,
Ash content of 0.1% by weight or less , which is obtained by blending 20 to 200 parts by weight of dicyandiamide having an average particle size of 100 μm or less with respect to 100 parts by weight of solid content of the resin aqueous dispersion.
The thermoplastic resin film is laminated on at least one surface of the sheet formed of the trace ash composition of
It has a limiting oxygen index of 26 or more at 0 μm and contains no phosphorus.
Self-extinguishing laminated flame retardant
Red. 2 . Polyolefin-based resin aqueous dispersion having a resin solid content of 30 to 75% by weight, ethylene-vinyl acetate copolymer aqueous dispersion, ethylene-vinyl acetate-vinyl versatate copolymer aqueous dispersion, ethylene-vinyl acetate-vinyl acrylate copolymer aqueous dispersion, acrylic-modified ethylene - is one or more aqueous resin dispersions selected or vinyl acetate copolymer aqueous dispersion, limited as described in item 1
Radioactive substances with a field oxygen index of 26 or higher and no phosphorus
Self-extinguishing laminated flame retardant sheet for preventing pollution due to quality. 3 . Polyolefin resin Aqueous aqueous dispersion containing 100 parts by weight of resin solids and 10 to 100 parts by weight of a melamine compound, and the limiting oxygen index described in item 1 or 2 is 26 or more and does not contain phosphorus. , Free
Self-extinguishing laminated flame-retardant sheet for preventing pollution by emissive substances. 4 . The melamine-based compound is melamine, the limiting oxygen index described in the item 3 is 26 or more and does not contain phosphorus,
Self-extinguishing laminated flame-retardant sheet for preventing contamination by radioactive substances
To. 5 . The melamine-based compound is melamine cyanurate, and the limiting oxygen index described in item 3 is 26 or more and phosphorus.
Self-extinguishing property for preventing contamination by radioactive substances that does not contain
Laminated flame retardant sheet. Regarding

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As the polyolefin resin aqueous dispersion used in the present invention, ethylene-vinyl acetate copolymer aqueous dispersion, ethylene-vinyl acetate-versa vinyl acetate copolymer aqueous dispersion, Ethylene-vinyl acetate-acrylic acid ester copolymer aqueous dispersion, acrylic modified ethylene-
Examples thereof include a vinyl acetate copolymer aqueous dispersion. Among them, the ethylene-vinyl acetate copolymer aqueous dispersion is preferable, and as the ethylene-vinyl acetate copolymer, a copolymer of 60 to 95% by weight of vinyl acetate and the balance ethylene is preferable, and the ethylene-vinyl acetate copolymer aqueous solution is preferable. The dispersion has a solid content of 30 to 75% by weight and a particle size of 0.
1~15μ m, viscosity 50～9000Cp, is preferably a pH 4-9, e.g., S-455, S-456, S-
467, S-500, S-752, S-753 (manufactured by Sumitomo Chemical Co., Ltd.) and the like are preferably used.

Polyurethane having a main structure of polyester, polyether or polycarbonate is used as the polyurethane, but a polyurethane having a polyester main structure is preferable from the viewpoint of flexibility, water resistance and adhesion. The polyurethane aqueous dispersion used in the present invention has a solid content of 25 to 70% by weight and a particle size of 0.01 to 10 μm.
m , viscosity 10 to 3000 cp, pH 4 to 9 are preferable, for example, Sumitomo Bayer Urethane Co., Ltd., Despacol U-42, Despacol U-53, Despacall U-54, Despacall KA8481, Asahi Denka Kogyo Co., Ltd., Adekabon. Titer HUX-38
0, ADEKA BON TITER HUX-232, ADEKA BON TITER HUX-290H, ADEKA BON TITER H
UX-35O, ADEKA BON TITER HUX-386
H, manufactured by Kansai Paint Co., Ltd., and RETAN WB-C. The polyurethane aqueous dispersion may be used alone, or may be used as a mixture with the polyolefin resin aqueous dispersion. Polyurethane water-based dispersion solid content 90 to 30% by weight, based on polyolefin resin water-based dispersion solid content 10 to 70
A weight percentage is preferred.

The present invention uses dicyandiamide as a flame retardant. Dicyandiamide has the chemical formula

[0008]

[Chemical 1]

## STR1 ## which is a compound having a melting point of 209.degree.
The ash content is 0.03% by weight or less, and the specific gravity is 1.40. Considering the dispersibility of the dicyandiamide in the aqueous dispersion resin, the average particle diameter is preferably 100 μm or less. It is more preferable that the average particle size is 5 to 20 μm.
Dicyandiamide is an aqueous dispersion resin solid content 1
Although it is added in an amount of 20 to 200 parts by weight with respect to 00 parts by weight, it has good compatibility with the ethylene-vinyl acetate copolymer aqueous dispersion and the polyurethane aqueous dispersion, and even if a large amount of these is blended with the resin, Viscosity increase of sparging is small. Also, there is almost no plate out. Dicyandiamide decomposes during combustion to generate ammonia gas, which provides self-extinguishing properties. If the amount is less than 20 parts by weight
The flame-retardant effect is small, and when the amount is 200 parts by weight or more, the viscosity of the aqueous dispersion increases, which makes it difficult to manufacture the aqueous flame-retardant resin dispersion. Examples of dicyandiamide include Epicure DICY 7A, Epicure DICY
7, epicure DICY 15, epicure DIC
Examples include Y 20 (produced by Yuka Shell Epoxy Co., Ltd.) and dicyandiamide (produced by Nippon Carbide Industry Co., Ltd.).

The reason why the thermoplastic resin film is laminated on at least one surface of the sheet formed of the aqueous dispersion resin containing dicyandiamide in the present invention is to reinforce the tensile strength of the flame-retardant sheet. This film may be of any type of resin, but the polyester film is formed by casting the flame-retardant aqueous resin dispersion onto a thermoplastic resin film and reducing shrinkage of the film due to heating during subsequent heating in a heating furnace. Is desirable. The other side of the thermoplastic resin film having the flame-retardant sheet is preferably an ethylene-vinyl acetate copolymer film having a slightly rubber elasticity so that it does not slip even when a person walks when laid on the floor. Further embossing is more desirable.

The thickness of the thermoplastic resin film is 5 to 50 μm.
m. A thicker one is preferable from the viewpoint of tensile strength reinforcement, and a thinner one is preferable from the viewpoint of flame retardancy and texture. 5-35 μm
Is preferable, and more preferably 5 to 25 μm. When the thickness of the flame-retardant sheet of the present invention is 50 μm or less, when the flame-retardant aqueous dispersion is cast on a thermoplastic resin film to produce a flame-retardant sheet with a knife coater (doctor blade) or the like, it is uniform. It becomes difficult to obtain a thick flame-retardant sheet, which causes a problem in manufacturing process. The texture becomes hard at 500μ m or more, the handling property is in bad flame retardant sheet.

The limiting oxygen index showing self-extinguishing property and flame retardancy is 26 or more. When it is 26 or less, self-extinguishing property and flame retardancy are insufficient, which is not preferable.

The melamine compounds used in the present invention include melamine and melamine cyanurate. Melamine preferably has a particle size of 50 μm or less, particularly 20 μm
The following are preferred. The flame retardancy has a synergistic effect with dicyandiamide, and 10 to 100 parts by weight is added to 100 parts by weight of the solid content of the polyolefin resin aqueous dispersion. When the amount is 10 parts by weight or less, the synergistic effect is small and 10
A synergistic effect becomes small even if it is 0 part by weight or more. For example, there are melamine manufactured by Yuka Melamine Co., Ltd. and melamine manufactured by Nissan Chemical Industries, Ltd. Melamine cyanurate has a particle size of 50
It is preferably not more than μm, particularly preferably not more than 20 μm. Flame retardancy has a synergistic effect with dicyandiamide, and is added in an amount of 10 to 100 parts by weight. If it is 10 parts by weight or less, the synergistic effect is small, and if it is 100 parts by weight or more, the synergistic effect is small. When added to an aqueous dispersion resin, melamine cyanurate may thicken even in a small amount depending on the type, but a melamine cyanurate surface-treated with a resin compound or an inorganic compound tends to have a small thickening, which is preferable. An example is MC-610 (manufactured by Nissan Chemical Industries, Ltd.).

In the present invention, the flame retardant is appropriately selected in kind and amount, and pigments, dyes, plasticizers, ultraviolet absorbers, light stabilizers, antioxidants, stabilizers, coupling agents, diluents, thickeners, foaming agents. Agents, dispersants, foaming agents, antifungal agents, antialgal agents, etc. can be used in combination.

[0015]

EXAMPLES The present invention will be specifically described with reference to examples.

Example 1 Ethylene-vinyl acetate copolymer aqueous dispersion S-7 into a planetary mixer (capacity 25 liters)
53 (Sumitomo Chemical Co., Ltd., solid content 50% by weight) 2
00 parts by weight, and then dicyandiamide Epicure DICY 7A (produced by Yuka Shell Epoxy Co., Ltd.,
100 parts by weight of an average particle size of 5 to 10 μm and an ash content of 0.05% or less) and an ultraviolet absorber tinupin 327 (manufactured by Ciba-Geigy)
0.3 parts by weight, antioxidant Irganox 1010
0.3 parts by weight (manufactured by Ciba-Gaigi Co., Ltd.) and 0.5 parts by weight of antifoaming agent Adecanate B1016 (manufactured by Asahi Denka Kogyo Co., Ltd.) are gradually added over about 5 minutes while stirring. Then 2
Stir for 0 minutes. Next, gradually increase the pressure reduction degree to 1
Vacuum degassing was performed at 0 mmHg for about 30 minutes, and then this mixture was kneaded by passing through a triple roll. Viscosity 3,860cp
(BM type viscometer, rotor V-6, 12 rpm, 25
A water-based flame-retardant resin dispersion (° C.) Was obtained. Width 12
A 0 cm, 25 μm thick polyester film is pulled out through a guide roll, a water-based flame-retardant resin dispersion is gradually injected onto the film with a hose, and the film is cast on one side of the film by a knife coater (doctor blade). After coating, temperature 80 ℃, 100 ℃, 120 ℃, 140
A flame-retardant sheet having a polyester film laminated on one surface by heat treatment in a heating furnace at ℃ was wound up with a winder. Next, a film of ethylene-vinyl acetate copolymer (vinyl acetate content 19% by weight) having a thickness of 12 μm was laminated on one surface by a dry lamination method to obtain a flame-retardant sheet having a thickness of 150 μm. The results of measuring the performance of the flame-retardant sheet are shown in Table 1.

Example 2 Ethylene-vinyl acetate copolymer S-7 in Example 1
Polyurethane Dispacol U-5 instead of 53
4 (manufactured by Sumitomo Bayer Urethane Co., Ltd., solid content: 50% by weight) was used in an amount of 200 parts by weight, and 40 parts by weight of dicyandiamide Epicure DICY 7A was added. The viscosity of the aqueous flame-retardant resin dispersion was 2,230 cp. Otherwise in the same manner as in Example 1, a flame-retardant sheet having a polyester film laminated on one surface was wound on a winder. The ethylene-vinyl acetate copolymer film was not laminated on one surface, and the film was laminated to obtain a flame-retardant sheet having only one surface. The thickness of the flame-retardant sheet was 130 μm.
The results of measuring the performance of the flame-retardant sheet are shown in Table 1.

Example 3 Ethylene-vinyl acetate copolymer S-7 in Example 1
Instead of 53, S-752 (Sumitomo Chemical Co., Ltd.,
60 parts by weight of solid content 50% by weight and 140 parts by weight of polyurethane dispacol U-54 (solid content 50% by weight) were added. Dicyandiamide Epicure DIC
80 parts by weight of Y 7A was added. The aqueous flame-retardant resin dispersion viscosity was 2,570 cp. Otherwise in the same manner as in Example 1, a flame-retardant sheet having a thickness of 180 μm was obtained. The results of measuring the performance of the flame-retardant sheet are shown in Table 1.
Shown in.

Example 4 In Example 1, dicyandiamide was epicured DI
Dicyandiamide de Instead of using CY 7A (Nippon Carbide Industries Co., Ltd., particle size 50 to 100 [mu] m, 0.03% or less ash content) 100 parts by weight of melamine (manufactured by Yuka melamine, Ltd.) were added 20 parts by weight. The viscosity of the aqueous flame-retardant resin dispersion was 4,180 cp. Otherwise in the same manner as in Example 1, a flame-retardant sheet having a thickness of 210 μm was obtained. The results of measuring the performance of the flame-retardant sheet are shown in Table 1.

Example 5 In Example 1, dicyandiamide was epicured DI
Dicyandiamide de Instead of using CY 7A (Nippon Carbide Industries Co., Ltd., particle size 50 to 100 [mu] m, 0.03% or less ash content) 100 parts by weight of melamine cyanurate MC-610 (Nissan Chemical Industries, Ltd.) 20 weight Parts were added. The viscosity of the aqueous flame-retardant resin dispersion was 4,470 cp. Otherwise in the same manner as in Example 1, a flame-retardant sheet having a thickness of 190 μm was obtained. The results of measuring the performance of the flame-retardant sheet are shown in Table 1.

Example 6 In Example 1, dicyandiamide was epicured DI
Instead of using CY 7A, 180 parts by weight of dicyandiamide (manufactured by Nippon Carbide Industry Co., Ltd., particle size 50-100 μm, ash content 0.03% or less) was added. The viscosity of the aqueous flame-retardant resin dispersion was 4,820 cp. Otherwise in the same manner as in Example 1, a flame-retardant sheet having a thickness of 320 μm was obtained. The results of measuring the performance of the flame-retardant sheet are shown in Table 1.

Example 7 Ethylene-vinyl acetate copolymer S-7 in Example 1
263 parts by weight of polyurethane Retan WB-C (manufactured by Kansai Paint Co., Ltd., solid content: 38% by weight) was used in place of 53, and dicyandiamide was Epicure DICY.
Dicyandiamide de instead of 7A (Nippon Carbide Co., Ltd., particle size 50~100μm, less than 0.03% ash)
100 parts by weight were added. Otherwise in the same manner as in Example 1, an aqueous flame-retardant resin dispersion having a viscosity of 2,350 cp was obtained. Using the aqueous flame-retardant resin dispersion, a flame-retardant sheet having a polyester film laminated on one surface was wound on a winder in the same manner as in Example 1. The ethylene-vinyl acetate copolymer film was not laminated on one side, and the film was laminated to obtain a flame-retardant sheet on one side. The thickness of the flame retardant sheet was 150 μm. The results of measuring the performance of the flame-retardant sheet are shown in Table 1.

Example 8 Ethylene-vinyl acetate copolymer S-7 in Example 1
263 parts by weight of polyurethane Retan WB-C (manufactured by Kansai Paint Co., Ltd., solid content: 38% by weight) was used in place of 53, and dicyandiamide was Epicure DICY.
Dicyandiamide de instead of 7A (Nippon Carbide Co., Ltd., particle size 50~100μm, less than 0.03% ash)
120 parts by weight, melamine (produced by Yuka Melamine Co., Ltd.) 2
0 parts by weight was added. Others are the same as in Example 1,
An aqueous flame-retardant resin dispersion having a viscosity of 3,490 cp was obtained. Using the aqueous flame-retardant resin dispersion, a flame-retardant sheet having a thickness of 95 μm was obtained in the same manner as in Example 1.
The results of measuring the performance of the flame-retardant sheet are shown in Table 1.

Comparative Example 1 Dicyandiamide Epicure DI in Example 1
The number of parts of CY 7A added was 10 parts by weight. An aqueous flame-retardant resin dispersion was manufactured in the same manner as in Example 1 except for the above. The viscosity of the aqueous flame-retardant resin dispersion was 1,250 cp. Otherwise in the same manner as in Example 1, a flame-retardant sheet having a thickness of 155 μm was obtained. The results of measuring the performance of the flame-retardant sheet are shown in Table 1.

Comparative Example 2 Dicyandiamide Epicure DI in Example 1
The number of added parts of CY 7A was set to 250 parts by weight. A water-based flame-retardant resin dispersion was prepared in the same manner as in Example 1 except that the viscosity of the water-resistant flame-retardant resin dispersion increased during stirring, and the dispersion could be poured and cast onto a polyester film. Could not be manufactured.

[0026]

[Table 1]

(Note) 1. The flame-retardant resin liquid in the table is an abbreviation for aqueous flame-retardant resin dispersion. 2. In the table, units of tensile strength, A and B are Kgf / 1.5 cm. 3.
Ash content <0.1 in the table indicates less than 0.1. 4. The methods of measuring various performances are as follows. (1) Oxygen index JIS K 7201 Support method classification: B-1 No. (2) Tensile test JIS Z-1702 (3) An appropriate amount of ash sample was sampled in a platinum crucible and carbonized on a hot plate, and then an electric furnace It was ashed at 850 ° C. for 30 minutes and weighed to obtain ash.

[0028]

INDUSTRIAL APPLICABILITY The present invention has self-extinguishing property, exhibits good flame retardancy when used, does not generate halogen or phosphorus when incinerated,
Has excellent effect with little residual ash after incineration.

Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 C08J 7/04 B05D 1/00-7/26 C09D 1/00-10/00 C09D 101 / 00-201/10

Claims (5)

(57) [Claims] 1. A polyolefin-based resin aqueous dispersion having a resin solid content of 30 to 75% by weight, and a resin solid content of 25 to
70% by weight of a polyurethane resin aqueous dispersion, 1 or 2 or more resin aqueous dispersions selected from 20 to 200 parts by weight based on 100 parts by weight of the solid content of the resin aqueous dispersion, the average particle size is 100 μm.
0.1 weight of ash made by blending the following dicyandiamide
A thermoplastic resin film is laminated on at least one surface of a sheet formed of a trace ash composition in an amount of 5% or less , and has a thickness of 5
0 to 500 μm, the limiting oxygen index is 26 or more, and phosphorus is included.
Self-extinguishing laminated layer to prevent contamination by radioactive substances
Flame retardant sheet. 2. An aqueous dispersion of a polyolefin resin, wherein the aqueous dispersion of the resin is 30 to 75% by weight of resin solids, an aqueous dispersion of ethylene-vinyl acetate copolymer, an aqueous dispersion of ethylene-vinyl acetate-vinyl versatate copolymer, ethylene-acetic acid. The limiting oxygen index according to claim 1, which is one or more resin aqueous dispersions selected from a vinyl-vinyl acrylate copolymer aqueous dispersion and an acrylic modified ethylene-vinyl acetate copolymer aqueous dispersion. 26 or more and no phosphorus
Self-extinguishing laminated flame retardant
Red. 3. The limiting oxygen index according to claim 1 or 2, wherein 10 to 100 parts by weight of the melamine compound is mixed with 100 parts by weight of the resin solid content of the aqueous polyolefin-based resin dispersion. Contains phosphorus
No, self-extinguishing layering prevention to prevent contamination by radioactive substances
Burning sheet. 4. The limiting oxygen index according to claim 3 , wherein the melamine compound is melamine , and phosphorus is included.
Self-extinguishing product to prevent contamination by radioactive substances not contained
Layer flame retardant sheet. 5. The limiting oxygen index according to claim 3 , wherein the melamine compound is melamine cyanurate.
Above, for preventing contamination by radioactive substances that do not contain phosphorus
Self-extinguishing laminated flame retardant sheet.