JP7557289B2 - Thermally expandable fireproof material - Google Patents

Description

The present invention relates to a thermally expandable fire-resistant material containing thermally expandable graphite.

In the field of construction, fireproof materials are used in building materials such as fittings, pillars, and wall materials for fire prevention. As fireproof materials, thermally expandable fireproof materials in which thermally expandable graphite is blended with resin in addition to flame retardants, inorganic fillers, etc. are used (see, for example, Patent Document 1). Such thermally expandable fireproof materials expand when heated, and the combustion residue forms a fireproof insulation layer, thereby exhibiting fireproof insulation performance.
A thermally expandable fire-resistant material containing thermally expandable graphite is placed, for example, in the gap between fittings such as doors and windows installed in openings of a building and the frames surrounding them, such as door frames and window frames, and in the event of a fire, the sheet expands in the thickness direction to close the gap between the fittings and the frames and prevent the fire from spreading.

JP 2017-141463 A

However, it has been found that even when a heat-expandable fire-resistant material containing heat-expandable graphite is used, in the event of a fire, over a long period of time, heat can cause fittings such as doors and windows to warp, widening the gap between the fittings and the frames. In such cases, the heat-expandable fire-resistant material may not be able to expand sufficiently to close the gap, making it impossible to prevent the fire from spreading.
Therefore, the present invention aims to provide a heat-expandable fire-resistant material that has superior heat expansion properties (late expansion properties) after a long period of time has passed during a fire compared to conventional fire-resistant materials, and that can easily close the gap between the building material and the frame material even after the gap has widened, thereby preventing the spread of fire.

As a result of intensive research to solve the above problems, the present inventors have found that the above problems can be solved by a thermally expandable fireproof material containing a resin, thermally expandable graphite A, and an expansion initiation retarder that delays the initiation of expansion of the thermally expandable graphite A.
That is, the present invention relates to the following [1] to [15].
[1] A thermally expandable fire-resistant material comprising a resin, thermally expandable graphite A, and an expansion initiation retarder that delays the initiation of expansion of the thermally expandable graphite A.
[2] The thermally expandable fireproof material according to the above [1], wherein the expansion initiation retarder is at least one selected from thermally expandable graphite B having a lower expansion initiation temperature than the thermally expandable graphite A, and a heat absorbing agent.
[3] The thermally expandable refractory material according to the above item [2], wherein the thermal expansion onset temperature of the thermally expandable graphite A is TA and the thermal expansion onset temperature of the thermally expandable graphite B is TB, and the difference between TA and TB (TA-TB) is 40°C or more.
[4] The ratio of the content of the thermally expandable graphite A to the content of the thermally expandable graphite B (content of the thermally expandable graphite A/content of the thermally expandable graphite B) is 10/90 to 90/10. The thermally expandable fireproof material according to [2] or [3] above.
[5] The thermally expandable refractory material according to any one of the above [2] to [4], wherein the thermal expansion onset temperature of the thermally expandable graphite A is TA and the endothermic onset temperature of the heat-absorbing agent is TC, and the difference between TA and TC (TA-TC) is 30°C or more.
[6] The ratio of the content of the thermally expandable graphite A to the content of the heat-absorbing agent (content of the thermally expandable graphite A/content of the heat-absorbing agent) is 90/10 to 99/1. The thermally expandable fireproof material according to any one of [2] to [5] above.
[7] The thermally expandable fireproof material according to any one of [1] to [6] above, wherein the total thermally expandable graphite content is 20 to 500 parts by mass per 100 parts by mass of the resin.
[8] The thermally expandable fire-resistant material according to any one of [1] to [7] above, further comprising a flame retardant.
[9] The thermally expandable fire-resistant material according to any one of [1] to [8] above, wherein the resin is a thermoplastic resin.
[10] The resin is at least one selected from the group consisting of ethylene-vinyl acetate copolymer, polyvinyl acetate resin, chloroprene rubber, phenol resin, polyacrylonitrile resin, and polycarbonate resin. The thermally expandable fire-resistant material according to any one of [1] to [9] above.
[11] The resin is at least one selected from an ethylene-vinyl acetate copolymer containing a high Vac component having a vinyl acetate content of 20% by mass or more, and a polyvinyl acetate resin. The thermally expandable fire-resistant material according to any one of [1] to [10] above.
[12] The thermally expandable fire-resistant material according to the above [10] or [11], wherein the ethylene-vinyl acetate copolymer contains a low MFR component having a melt flow rate (MFR) at 190°C of 8.0 g/10 min or less.
[13] The thermally expandable fire-resistant material according to any one of [1] to [12] above, wherein the resin is a phenolic resin.
[14] The thermally expandable fire-resistant material according to the above [13], wherein the phenolic resin is a novolac type.
[15] The thermally expandable fireproof material according to any one of [1] to [14] above, further comprising a crosslinking agent.

According to the present invention, it is possible to provide a heat-expandable fire-resistant material that has excellent heat expansion properties even after a long time has passed during a fire, and that can easily close the gap between the fitting and the frame material even after the gap has widened, thereby preventing the spread of fire. In this specification, excellent heat expansion properties even after a long time has passed during a fire are also referred to as excellent late-stage expansion properties.

[Thermal expansion fireproof material]
The thermally expandable fireproof material of the present invention is a thermally expandable fireproof material containing a resin, thermally expandable graphite A, and an expansion start retarder that delays the start of expansion of the thermally expandable graphite A. Hereinafter, the thermally expandable fireproof material of the present invention may also be simply referred to as a fireproof material.

The fire-resistant material of the present invention contains thermally expandable graphite A. This allows the gap between the fittings and the frame material to be blocked in the event of a fire, thereby preventing the spread of fire.
In the present invention, when the fire-resistant material contains one type of thermally-expandable graphite, the one type of thermally-expandable graphite is referred to as thermally-expandable graphite A, and when the fire-resistant material contains two or more types of thermally-expandable graphite, the thermally-expandable graphite having the highest thermal expansion initiation temperature is referred to as thermally-expandable graphite A, and the others are referred to as thermally-expandable graphite B.

(Expansion start retarder)
The thermally expandable fireproof material of the present invention contains an expansion start retarder that delays the start of expansion of the thermally expandable graphite A. By containing the expansion start retarder, the later expansion property of the fireproof material is improved, and therefore, even after the gap between the fitting and the frame material has widened, the gap can be easily blocked, and the spread of fire can be prevented.
The expansion start retarder is a compound capable of delaying the expansion start of thermally expandable graphite A by the action of heat insulation or heat absorption, and the type thereof is not limited. Examples of the expansion start retarder include thermally expandable graphite B, which has a lower expansion start temperature than thermally expandable graphite A, heat absorption agents, and foaming agents, but from the viewpoint of enhancing the later expansion property, it is preferable that the expansion start retarder be at least one selected from thermally expandable graphite B and heat absorption agents.

(Thermal Expandable Graphite)
The thermally expandable graphite B, which is an expansion initiation retarder for the thermally expandable graphite A, has a lower expansion initiation temperature than the thermally expandable graphite A. As a result, in the event of a fire, the thermally expandable graphite B expands before the thermally expandable graphite A, forming an expansion insulating layer around the thermally expandable graphite A, which is thought to delay the initiation of expansion of the thermally expandable graphite A. This increases the later expansion of the fire-resistant material.

From the viewpoint of further delaying the onset of expansion of the thermally-expandable graphite A, when the thermal expansion onset temperature of the thermally-expandable graphite A is TA and the thermal expansion onset temperature of the thermally-expandable graphite B is TB, the difference between TA and TB (TA-TB) is preferably 40°C or more, more preferably 60°C or more, and even more preferably 80°C or more.
From the viewpoint of enhancing the late expansion property, TA is preferably 160° C. or more, more preferably 170° C. or more, even more preferably 190° C. or more, and usually 300° C. or less. From the viewpoint of easily adjusting the difference between TA and TB within a desired range, TB is preferably 160° C. or less, more preferably 150° C. or less, even more preferably 130° C. or less, and usually 100° C. or more.
The fireproof material of the present invention may contain a plurality of thermally expandable graphites B. In this case, TB is a weighted average value calculated from the expansion start temperatures and contents of the individual thermally expandable graphites.
The expansion starting temperature of the thermally expandable graphite can be measured using a rheometer, and the expansion starting temperature is determined as the temperature at which the load increases due to the expansion of the thermally expandable graphite when the thermally expandable graphite is heated at a constant heating rate. The detailed measurement method is as described in the Examples.

The ratio of the content of thermally expandable graphite A to the content of thermally expandable graphite B (content of thermally expandable graphite A/content of thermally expandable graphite B) is preferably 10/90 to 90/10, more preferably 20/80 to 80/20, and even more preferably 40/60 to 60/40, from the viewpoint of enhancing the later expansion properties of the fireproof material.

When thermally expandable graphite A and thermally expandable graphite B are used in combination, from the viewpoint of increasing the later expansion of the fireproof material, the content of thermally expandable graphite A is preferably 10 to 250 parts by mass, more preferably 25 to 150 parts by mass, and even more preferably 50 to 100 parts by mass, relative to 100 parts by mass of resin. The content of thermally expandable graphite B is preferably 10 to 250 parts by mass, more preferably 25 to 150 parts by mass, and even more preferably 50 to 100 parts by mass, relative to 100 parts by mass of resin.

The total content of thermally expandable graphite contained in the fireproof material is preferably 20 to 500 parts by mass, more preferably 50 to 300 parts by mass, even more preferably 100 to 250 parts by mass, and even more preferably 110 to 200 parts by mass, per 100 parts by mass of resin, from the viewpoint of increasing the later expansion property of the fireproof material. If the content of thermally expandable graphite is equal to or greater than these lower limits, it becomes easier to increase the expansion pressure of the thermally expandable fireproof material. If the content of thermally expandable graphite is equal to or less than these upper limits, shape retention, processability, etc. are improved.

The fireproof material of the present invention contains the above-mentioned thermally expandable graphite A and, if necessary, thermally expandable graphite B. These thermally expandable graphites are conventionally known substances that expand when heated, and are produced by treating raw material powders such as natural scaly graphite, pyrolytic graphite, and kish graphite with a strong oxidizing agent to produce graphite intercalation compounds. Examples of the strong oxidizing agent include inorganic acids such as concentrated sulfuric acid, nitric acid, and selenic acid, concentrated nitric acid, perchloric acid, perchlorates, permanganates, dichromates, and hydrogen peroxide. Thermally expandable graphite is a crystalline compound that maintains the layered structure of carbon.
The thermally expandable graphite may be subjected to a neutralization treatment. That is, the thermally expandable graphite obtained by treating with a strong oxidizing agent or the like as described above may be further neutralized with ammonia, an aliphatic lower amine, an alkali metal compound, an alkaline earth metal compound, or the like.

The thermally expandable graphite in the present invention has an average aspect ratio of preferably at least 15, more preferably at least 20, and usually at most 1000. When the average aspect ratio of the thermally expandable graphite is equal to or more than these lower limit values, the expansion pressure of the refractory material is easily increased.
The aspect ratio of the thermally expandable graphite is determined by measuring the maximum dimension (major axis) and the minimum dimension (minor axis) of 10 or more (e.g., 50) pieces of thermally expandable graphite, and averaging the ratio (maximum dimension/minimum dimension). Note that the thermally expandable graphites A and B in the present invention may have the same or different average aspect ratios.

The average particle size of the thermally expandable graphite is preferably 50 to 500 μm, and more preferably 100 to 400 μm. The average particle size of the thermally expandable graphite is determined as the average value of the maximum dimensions of 10 or more (e.g., 50) pieces of thermally expandable graphite.
The minimum and maximum dimensions of the thermally expandable graphite can be measured, for example, by using a field emission scanning electron microscope (FE-SEM). The thermally expandable graphites A and B in the present invention may have the same or different average particle diameters.

(Thermal absorption agent)
In the present invention, a heat absorbing agent can be used as an expansion start retarder. It is considered that by using the heat absorbing agent, the periphery of the thermally expandable graphite A is absorbed by the heat absorbing agent during a fire, so that the expansion of the thermally expandable graphite A is delayed and the later expansion property of the fireproof material is enhanced.
The endothermic agent used as the expansion initiation retarder has an endothermic onset temperature equal to or lower than the expansion initiation temperature of thermally expandable graphite A. That is, when the endothermic onset temperature of the endothermic agent is taken as TC, the difference (TA-TC) between the thermal expansion initiation temperature TA of thermally expandable graphite A and TC is 0°C or more. The difference (TA-TC) between TA and TC is preferably 10°C or more, and more preferably 30°C or more. When the value of TA-TC is in such a range, the expansion initiation of thermally expandable graphite A is easily delayed.
The fireproof material of the present invention may contain a plurality of endothermic agents. In this case, TC is a weighted average value calculated from the endothermic onset temperatures and contents of the plurality of endothermic agents.
The endothermic onset temperature of the endothermic agent can be measured by a thermogravimetric differential thermal analyzer (TG-DTA), specifically, by the method described in the Examples.

The ratio of the content of thermally expandable graphite A to the content of the heat-absorbing agent in the fire-resistant material (content of thermally expandable graphite A/content of heat-absorbing agent) is preferably 90/10 to 99/1, more preferably 92/8 to 98/2, and further preferably 94/6 to 96/4, from the viewpoint of enhancing the late expansion property of the fire-resistant material.
The content of the heat-absorbing agent in the fire-resistant material is preferably 0.5 to 15 parts by mass, more preferably 2 to 10 parts by mass, and even more preferably 4 to 8 parts by mass, relative to 100 parts by mass of the resin, from the viewpoint of increasing the late expansion property of the fire-resistant material and improving moldability.

The endothermic amount of the endothermic agent is preferably 500 J/g or more, more preferably 600 J/g or more, and even more preferably 900 J/g or more. When the endothermic amount of the endothermic agent is within the above range, the heat absorption is improved, and the fire resistance is better. The endothermic amount of the endothermic agent is usually 4000 J/g or less, preferably 3000 J/g or less, and even more preferably 2000 J/g or less.
The endothermic heat can be measured using a thermogravimetric differential thermal analyzer (TG-DTA), specifically, by the method described in the examples.

The average particle size of the heat absorbing agent is more preferably 0.5 to 60 μm, further preferably 0.8 to 40 μm, and even more preferably 0.8 to 10 μm. When the average particle size of the heat absorbing agent is within the above range, the dispersibility of the heat absorbing agent in the fireproof material is improved, and the heat absorbing agent can be uniformly dispersed in the resin.
The average particle size of the heat absorbing agent and the flame retardant described below is the median diameter (D50) value measured by a laser diffraction/scattering type particle size distribution measuring device.

The type of the heat absorbing agent is not particularly limited, but examples thereof include metal hydroxides, boron compounds, and metal salts.
Examples of metal hydroxides include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, and hydrotalcite.
The boron-based compound may be zinc borate, etc. Zinc borate may be a hydrate such as 2ZnO.3B ₂ O _{5.3.5H 2} O.
The metal salts include calcium sulfate, magnesium sulfate, etc., and the metal salts may be hydrates.
Among these, calcium sulfate, aluminum hydroxide, calcium hydroxide, etc. are preferred as the heat absorbing agent.

The fireproof material of the present invention may contain a foaming agent as an expansion start retarder. As the foaming agent, either an organic foaming agent or an inorganic foaming agent can be used without any particular limitation.
Examples of organic foaming agents include compounds having a nitroso group such as N,N'-dinitrosopentamethylenetetramine, compounds having an azo group such as azodicarbonamide and barium azodicarboxylate, 4,4-oxybis(benzenesulfonylhydrazide), hydrazodicarbonamide, etc. Examples of inorganic foaming agents include sodium hydrogen carbonate, etc.
When a foaming agent is used, the amount of the foaming agent is not particularly limited, but is preferably 0.05 to 10 parts by mass, and more preferably 0.1 to 8 parts by mass, per 100 parts by mass of the resin.

(resin)
The fire-resistant material of the present invention contains a resin in which thermally expandable graphite A, an expansion initiation retarder, etc. are dispersed.
The resin contained in the fireproof material of the present invention is not particularly limited, but is preferably a thermoplastic resin. Examples of the resin include, but are not particularly limited to, polyolefin resins such as polypropylene resin, polyethylene resin, and ethylene-vinyl acetate copolymer, polyvinyl acetate resin, polyvinyl chloride resin, and rubber-based resins such as chloroprene rubber, fluororesins such as polytetrafluoroethylene, phenol resins, polycarbonate resins, and polyacrylonitrile resins.
Among these, from the viewpoint of increasing the late expansion property and expansion pressure of the fireproof material and improving the fire resistance, the resin is preferably at least one selected from the group consisting of ethylene-vinyl acetate copolymer, polyvinyl acetate resin, chloroprene rubber, phenol resin, polyacrylonitrile resin, and polycarbonate resin.

<Ethylene-vinyl acetate copolymer, polyvinyl acetate>
Among the above-mentioned resins, resins having a high vinyl acetate content are preferred from the viewpoint of increasing the later expansion property of the fireproof material and improving its fire resistance. Specifically, the resin is preferably at least one selected from ethylene-vinyl acetate copolymers containing a high Vac component with a vinyl acetate content of 20% by mass or more, and polyvinyl acetate resins, and more preferably polyvinyl acetate resins. The high Vac component with a vinyl acetate content of 20% by mass or more means an ethylene-vinyl acetate copolymer component with a vinyl acetate content of 20% by mass or more. Ethylene-vinyl acetate copolymers and polyvinyl acetate resins are non-chlorine-based resins, so they are unlikely to generate dioxins, and can be kneaded with thermally expandable graphite at relatively low temperatures without containing a plasticizer, and the moldability of the fireproof material is also good, so they are preferably used as resins contained in the fireproof material.

The vinyl acetate content of the high Vac component is preferably 25% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, and even more preferably 70% by mass or more, from the viewpoint of increasing the late expansion property of the fireproof material.

The ethylene-vinyl acetate copolymer may contain an ethylene-vinyl acetate copolymer component (low Vac component) having a vinyl acetate content of less than 20% by mass, as long as the effect of the present invention is not impaired. From the viewpoint of increasing the late expansion property and expansion pressure of the fireproof material, the content of the high Vac component is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 100% by mass, based on the total amount of the ethylene-vinyl acetate copolymer.

From the viewpoint of increasing the expansion pressure of the fireproof material and improving the moldability, the ethylene-vinyl acetate copolymer preferably contains an ethylene-vinyl acetate copolymer component (hereinafter also referred to as a low MFR component) having a melt flow rate (MFR) at 190° C. of 8.0 g/10 min or less. The melt flow rate (MFR) of the low MFR component at 190° C. is more preferably 6.0 g/10 min or less, and even more preferably 1.0 g/10 min or less. From the viewpoint of the moldability of the fireproof material, the melt flow rate (MFR) of the low MFR component at 190° C. is preferably 0.05 g/10 min or more, more preferably 0.1 g/10 min or more, and even more preferably 0.3 g/10 min or more.
The melt flow rate of the ethylene-vinyl acetate copolymer at 190° C. is a value measured under a load of 2.16 kg in accordance with JIS K7210:1999.

Based on the total amount of ethylene-vinyl acetate copolymer, the content of low MFR components is preferably 70% by mass or more, and more preferably 90% by mass or more.

Note that MFR and vinyl acetate content are separate parameters that describe the structure of an ethylene-vinyl acetate copolymer, so there are components that are both low MFR components and high Vac components.

When using a high Vac component having a vinyl acetate content of 20% by mass or more and less than 50% by mass among ethylene-vinyl acetate copolymers, the high Vac component is preferably the above-mentioned low MFR component from the viewpoint of increasing the expansion pressure and improving fire resistance, etc. In other words, the MFR (190°C) of the high Vac component is preferably 8.0 g/10 min or less, more preferably 6.0 g/10 min or less, even more preferably 1.0 g/10 min or less, and preferably 0.05 g/10 min or more, more preferably 0.1 g/10 min or more, even more preferably 0.3 g/10 min or more.
When using a high Vac component having a vinyl acetate content of 50% by mass or more among ethylene-vinyl acetate copolymers, the Mooney viscosity ML(1+4) of the high Vac component at 100°C is preferably 10 to 50, more preferably 20 to 40, from the viewpoints of increasing the expansion pressure and improving fire resistance.

Polyvinyl acetate resin is a homopolymer of vinyl acetate, and by using this as the resin contained in the fireproof material, the late expansion property of the fireproof material is further increased, and the fire resistance is effectively improved. From the viewpoint of improving the moldability of the fireproof material while increasing the expansion pressure, the weight average molecular weight of the polyvinyl acetate resin is preferably 100,000 to 1,000,000, more preferably 200,000 to 600,000, and even more preferably 300,000 to 500,000. In this specification, the weight average molecular weight is a standard polystyrene equivalent value obtained by measurement by gel permeation chromatography (GPC).

<Resin: Chloroprene rubber>
Chloroprene rubber can reduce the proportion of carbon contained in the fire-resistant material, and is therefore preferably used as a resin contained in the fire-resistant material from the viewpoint of enhancing fire resistance.
As the chloroprene rubber, a sulfur-modified type (G type), a non-sulfur-modified type (W type), etc. can also be used.
The Mooney viscosity ML(1+4) of the chloroprene rubber at 100° C. is preferably from 60 to 120, more preferably from 70 to 90. The chloroprene rubber having the Mooney viscosity ML(1+4) at 100° C. in the above range is likely to increase the expansion pressure of the fire-resistant material.
In this specification, the Mooney viscosity is measured in accordance with JIS K6300.

When chloroprene rubber is used, the fireproof material preferably contains a plasticizer, which will be described later. From the viewpoint of improving the moldability of the fireproof material, among the plasticizers described later, aliphatic ester plasticizers are preferred, among which aliphatic ester plasticizers having an ether bond are more preferred, and dibutoxyethoxyethyl adipate is even more preferred. Commercially available products of dibutoxyethoxyethyl adipate include, for example, Adeka Cizer RS-107 manufactured by ADEKA Corporation, which is called an ether ester adipate type. The amount of plasticizer used relative to the resin will be described later.

<Resin: Phenol resin>
The fireproof material of the present invention preferably uses a phenolic resin as the resin. By using a phenolic resin, the late expansion property of the fireproof material is likely to be increased, and the fire resistance is likely to be improved.
The phenolic resin is not particularly limited, but from the viewpoint of improving the moldability of the fireproof material, a novolac type phenolic resin is preferred.
Novolac-type phenolic resins are resins obtained by reacting phenols with aldehydes in the presence of an acid catalyst. Here, the phenols are compounds having a phenol skeleton, mainly phenol, but also cresol, alkylphenols, etc. Examples of the alkylphenols include p-t-butylphenol, p-octylphenol, and p-nonylphenol.
Examples of the aldehydes that can be used include formaldehyde, furfural, higher aldehydes, etc. The acid catalysts can be organic or inorganic acids, and examples of the acid catalysts that can be used include strong acids such as oxalic acid, sulfuric acid, and paratoluenesulfonic acid, and metal salt catalysts such as Ca, Zn, Cd, Pb, and Co.

<Resin: Specific resin>
The fireproof material of the present invention can enhance the late expansion property of the fireproof material by containing at least one specific resin selected from polycarbonate resin, polyacrylonitrile resin, polyimide, polyether ether ketone (PEEK), and fluororesin. For example, even when an ethylene-vinyl acetate copolymer consisting of only the low Vac component is used as the resin, the late expansion property of the fireproof material can be enhanced and the fire resistance can be improved by using the specific resin in combination. The specific resin is preferably at least one selected from polycarbonate resin and polyacrylonitrile resin.
From the viewpoint of improving the moldability of the fire-resistant material, it is preferable to use at least one resin selected from ethylene-vinyl acetate copolymer and polyvinyl acetate in combination with the specific resin, and it is more preferable to use the ethylene-vinyl acetate copolymer in combination with the specific resin.
When the specific resin is used, the content of the specific resin is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 30% by mass or less, based on the total amount of resin contained in the fireproof material. When the content of the specific resin is equal to or more than these lower limits, the late expansion property of the fireproof material can be increased, and the fire resistance can be improved. When the content of the specific resin is equal to or less than these upper limits, the moldability of the fireproof material can be improved.

As the resin, only the specific resin may be used alone, but in this case, it is preferable to use a plasticizer in combination from the viewpoint of improving the moldability of the fireproof material. The type and amount of plasticizer to be used will be described later.

(Plasticizer)
The fireproof material of the present invention may contain a plasticizer. By using a plasticizer, moldability is likely to be good. When a plasticizer is used, the content of the plasticizer is not particularly limited, but is preferably 10 to 200 parts by mass, more preferably 20 to 60 parts by mass, relative to 100 parts by mass of the resin. When the content of the plasticizer is equal to or greater than these lower limits, the moldability of the fireproof material is improved. When the content of the plasticizer is equal to or less than these upper limits, the late expansion property of the fireproof material is easily improved, and the expansion pressure is easily increased, thereby improving the fireproofness.

Specific examples of plasticizers include di-2-ethylhexyl phthalate (DOP), di-n-octyl phthalate, diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), diundecyl phthalate (DUP), or phthalate esters of higher alcohols or mixed alcohols having 10 to 13 carbon atoms, di-2-ethylhexyl adipate (DOA), diisobutyl adipate (DIBA), dibutyl adipate (DBA), di-n-octyl adipate, di- Examples include aliphatic ester plasticizers such as n-decyl adipate, diisodecyl adipate, di-2-ethylhexyl azelate, dibutyl sebacate, di-2-ethylhexyl sebacate, and dibutoxyethoxyethyl adipate; trimellitic acid ester plasticizers such as tri-2-ethylhexyl trimellitate (TOTM), tri-n-octyl trimellitate, tridecyl trimellitate, triisodecyl trimellitate, and di-n-octyl-n-decyl trimellitate; and process oils such as mineral oil.

(Crosslinking Agent)
The fireproof material of the present invention may contain a crosslinking agent. By using the crosslinking agent, crosslinking of the resin proceeds due to heat during a fire, and the later expansion property of the fireproof material increases, improving the fireproof property. In addition, as the crosslinking of the resin proceeds, the viscosity increases, and the expansion pressure also increases, improving the fireproof property.

As the crosslinking agent, any known agent can be used without limitation, and examples thereof include organic peroxides and azo compounds.
Examples of organic peroxides include 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 3-di-t-butyl peroxide, t-dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne, dicumyl peroxide, α,α'-bis(t-butylperoxyisopropyl)benzene, n-butyl-4,4-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)butane, 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, t-butylperoxybenzoate, benzoyl peroxide, and t-butylperoxy-2-ethylhexyl carbonate.
Examples of the azo compound include azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile).

Among the above-mentioned crosslinking agents, those that are unlikely to undergo a crosslinking reaction at the temperature at which the components are kneaded when manufacturing the fireproof material (e.g., 70°C to 150°C) and that are likely to undergo a crosslinking reaction of the resin due to the heat of a fire are preferred. From this perspective, preferred crosslinking agents include dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and t-butylperoxy-2-ethylhexyl monocarbonate.

When the fireproof material contains a crosslinking agent, the content of the crosslinking agent is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 7 parts by mass, and even more preferably 1 to 5 parts by mass, per 100 parts by mass of the resin.

(Flame retardant)
The fire-resistant material of the present invention preferably contains a flame retardant, which improves fire resistance.
Examples of the flame retardant include various phosphoric acid esters such as triphenyl phosphate (triphenyl phosphate), tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, and xylenyl diphenyl phosphate, metal phosphates such as sodium phosphate, potassium phosphate, and magnesium phosphate, metal phosphites such as sodium phosphite, potassium phosphite, magnesium phosphite, and aluminum phosphite, ammonium polyphosphate, red phosphorus, etc. Examples of the flame retardant also include compounds represented by the following general formula (1).

In the general formula (1), ^R1 and ^R3 are the same or different and represent hydrogen, a linear or branched alkyl group having 1 to 16 carbon atoms, or an aryl group having 6 to 16 carbon atoms. ^R2 represents a hydroxyl group, a linear or branched alkyl group having 1 to 16 carbon atoms, a linear or branched alkoxyl group having 1 to 16 carbon atoms, an aryl group having 6 to 16 carbon atoms, or an aryloxy group having 6 to 16 carbon atoms.

Specific examples of the compound represented by the general formula (1) include methylphosphonic acid, dimethyl methylphosphonate, diethyl methylphosphonate, ethylphosphonic acid, n-propylphosphonic acid, n-butylphosphonic acid, 2-methylpropylphosphonic acid, t-butylphosphonic acid, 2,3-dimethyl-butylphosphonic acid, octylphosphonic acid, phenylphosphonic acid, dioctylphenylphosphonate, dimethylphosphinic acid, methylethylphosphinic acid, methylpropylphosphinic acid, diethylphosphinic acid, dioctylphosphinic acid, phenylphosphinic acid, diethylphenylphosphinic acid, diphenylphosphinic acid, and bis(4-methoxyphenyl)phosphinic acid. The flame retardants may be used alone or in combination of two or more.

As the flame retardant of the present invention, boron compounds and metal hydroxides can also be used.
The boron-based compound may, for example, be zinc borate.
Examples of metal hydroxides include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, hydrotalcite, etc. When a metal hydroxide is used, water is generated by the heat generated by ignition, and the fire can be quickly extinguished.

Among the flame retardants, from the standpoint of safety, cost, etc., red phosphorus, phosphate esters such as triphenyl phosphate (triphenyl phosphate), aluminum phosphite, ammonium polyphosphate, and zinc borate are preferred. Among these, aluminum phosphite and ammonium polyphosphate are more preferred, and aluminum phosphite is even more preferred. Aluminum phosphite has expansive properties, so that fireproof materials containing it tend to increase the expansion pressure and more effectively improve fire resistance.

The average particle size of the flame retardant is preferably 1 to 200 μm, more preferably 1 to 60 μm, even more preferably 3 to 40 μm, and even more preferably 5 to 20 μm. When the average particle size of the flame retardant is within the above range, the dispersibility of the flame retardant in the fire-resistant material is improved, and the flame retardant can be uniformly dispersed in the resin and the amount of the flame retardant mixed in the resin can be increased. When the average particle size is outside the above range, the flame retardant is difficult to disperse in the resin, and it becomes difficult to uniformly disperse the flame retardant in the resin and to mix a large amount of the flame retardant in the resin.
The average particle size of the flame retardant is the median diameter (D50) measured by a laser diffraction/scattering type particle size distribution measuring device.

The content of the flame retardant in the fire-resistant material of the present invention is preferably 15 to 1000 parts by mass, more preferably 20 to 300 parts by mass, and even more preferably 30 to 100 parts by mass, per 100 parts by mass of resin. If the content of the flame retardant is equal to or greater than these lower limits, the fire resistance of the fire-resistant material is improved. If the content of the flame retardant is equal to or less than these upper limits, the flame retardant is easily dispersed uniformly in the resin, resulting in excellent moldability, etc.

(Inorganic filler)
The fire-resistant material of the present invention may further contain an inorganic filler other than the flame retardant and the thermally expandable graphite.
The inorganic filler other than the flame retardant and the thermally expandable graphite is not particularly limited, and examples thereof include metal oxides such as alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, and ferrite, metal carbonates such as basic magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate, strontium carbonate, and barium carbonate, silica, diatomaceous earth, dawsonite, barium sulfate, talc, clay, mica, montmorillonite, bentonite, activated clay, sepiolite, imogolite, sericite, glass fiber, glass beads, silica-based balloons, aluminum nitride, boron nitride, silicon nitride, carbon black, graphite, carbon fiber, carbon balloons, charcoal powder, various metal powders, potassium titanate, magnesium sulfate, lead zirconate titanate, zinc stearate, calcium stearate, aluminum borate, molybdenum sulfide, silicon carbide, stainless steel fiber, various magnetic powders, slag fiber, fly ash, and dewatered sludge. These inorganic fillers may be used alone or in combination of two or more kinds.

The average particle size of the inorganic filler is preferably 0.5 to 100 μm, and more preferably 1 to 50 μm. When the content is low, inorganic fillers with a small particle size are preferred from the viewpoint of improving dispersibility, while when the content is high, the viscosity of the refractory material increases and moldability decreases as the content increases, so a large particle size is preferred.

When the fire-resistant material of the present invention contains an inorganic filler other than a flame retardant and thermally expandable graphite, the content is preferably 10 to 300 parts by mass, more preferably 10 to 200 parts by mass, per 100 parts by mass of resin. When the content of the inorganic filler is within the above range, the mechanical properties of the fire-resistant material can be improved.

The fireproof material of the present invention can contain various additive components as required within the range that does not impair the object of the present invention.
The type of the additive component is not particularly limited, and various additives can be used. Examples of such additives include lubricants, shrinkage inhibitors, crystal nucleating agents, colorants (pigments, dyes, etc.), ultraviolet absorbers, antioxidants, antiaging agents, dispersants, gelation accelerators, fillers, reinforcing agents, flame retardant assistants, antistatic agents, surfactants, vulcanizing agents, and surface treatment agents. The amount of additive added can be appropriately selected within a range that does not impair moldability, etc. The additives may be used alone or in combination of two or more.

(Expansion Pressure)
The fireproof material of the present invention preferably has an expansion pressure of 3.0 N/cm ² or more. When the fireproof material has an expansion pressure of 3.0 N/cm ² or more, even if it is exposed to flames for a long period of time in the event of a fire, the force for closing the gaps in the fittings can be maintained, the fireproof material is less likely to peel off from the fittings, and the fire resistance is improved.
From the viewpoint of improving fire resistance, the expansion pressure of the thermally expandable fireproof material is preferably 5.0 N/cm ² or more, more preferably 7.0 N/cm ² or more, and even more preferably 10.0 N/cm ² or more. The higher the expansion pressure of the thermally expandable fireproof material, the better, but in practical use, it is 50 N/cm ² or less.
The expansion pressure of the fireproof material can be adjusted by the amount of thermally expandable graphite, the type of resin, whether or not a crosslinking agent is used, and the like.

The expansion pressure in the present invention is the expansion pressure at 500° C., and is measured as follows.
(1) Prepare a sheet-like fireproof material having a thickness of 1.8 mm, a width of 25 mm, and a length of 25 mm.
(2) Place a hot plate and a force gauge 1.2 cm away from the surface of the hot plate.
(3) The surface of the hot plate is heated to 500°C, the above-mentioned sheet-like fireproof material is placed on the surface of the hot plate, and a ceramic plate (made of calcium silicate, thickness 2 mm, width 30 mm, length 30 mm) is further placed on the fireproof material.
(4) When the fireproof material is heated on a hot plate at 500° C. for 250 seconds, the maximum stress measured with a force gauge is divided by the area of the jig to obtain the expansion pressure.

The expansion ratio of the fireproof material of the present invention is not particularly limited, but from the viewpoint of obtaining good fire resistance, it is preferably 10 to 500 times, more preferably 50 to 300 times, and even more preferably 100 to 250 times.
The expansion ratio can be determined by heating a sheet-like refractory material having a thickness of 1.8 mm, a width of 25 mm and a length of 25 mm at 600°C for 30 minutes and dividing the thickness of the refractory material after heating by the thickness of the refractory material before heating.

The fireproof material is preferably in sheet form, and the thickness is not particularly limited, but from the standpoint of fire resistance and ease of handling, a thickness of 0.2 to 10 mm is preferable, and 0.5 to 3.0 mm is more preferable.

(Method of manufacturing fireproof material)
The fireproof material of the present invention can be produced, for example, as follows.
First, predetermined amounts of thermally expandable graphite A, resin, expansion initiation retarder, plasticizer which is blended as necessary, flame retardant, crosslinking agent, inorganic filler, and other components are kneaded in a kneading machine such as a kneading roll to obtain a fire-resistant resin composition.
Next, the obtained fire-resistant resin composition is molded into a sheet or the like by a known molding method such as press molding, calendar molding, extrusion molding, etc., to obtain a fire-resistant material.
The temperature during kneading and the temperature during molding into a sheet are preferably lower than the expansion initiation temperature of the thermally expandable graphite, and when a crosslinking agent is added, the temperature is preferably such that the crosslinking agent is unlikely to crosslink. Therefore, the kneading temperature is preferably 70 to 150° C., more preferably 90 to 140° C. The temperature during molding into a sheet is preferably 80 to 130° C., more preferably 90 to 120° C.

(Laminated sheet)
The fireproof material of the present invention may be laminated with other sheet members or pressure-sensitive adhesive layers to form a laminate sheet. The laminate sheet includes, for example, a substrate and a fireproof material laminated on one or both sides of the substrate. The substrate is usually a woven fabric or nonwoven fabric. The fibers used for the woven fabric or nonwoven fabric are not particularly limited, but are preferably noncombustible or semi-noncombustible materials, such as glass fibers, ceramic fibers, cellulose fibers, polyester fibers, carbon fibers, graphite fibers, and thermosetting resin fibers.
The laminate sheet can be obtained, for example, by forming the fire-resistant resin composition into a sheet on a substrate.

The laminate sheet may also include a fireproof material and an adhesive layer. The adhesive layer may be laminated on one or both sides of the fireproof material, for example.
Furthermore, the laminate sheet may include a fireproof material, a substrate, and an adhesive layer. Such a laminate sheet may have a fireproof material on one side of the substrate and an adhesive layer on the other side, or a fireproof material and an adhesive layer may be provided in this order on one side of the substrate. The adhesive layer can be formed, for example, by transferring an adhesive coated on a release paper to the laminate sheet.

The fireproof material of the present invention and the laminated sheet using the same can be used specifically for various fittings in detached houses, apartment buildings, high-rise houses, high-rise buildings, commercial facilities, public facilities, and the like, various vehicles such as automobiles and trains, ships, and aircraft, among which it is preferable to use it for fittings. Specific examples of fittings that can be used include, but are not limited to, walls, beams, pillars, floors, bricks, roofs, boards, windows, shoji screens, doors, sliding doors, transoms, wiring, and piping. The fireproof material of the present invention and the laminated sheet using the same can be applied, particularly to gaps in fittings such as windows and doors, to prevent flames from penetrating through the gaps in the event of a fire, etc.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these.

[Evaluation method]
(I) Late Expansion The fireproof materials of each Example and Comparative Example were cut to a predetermined size (thickness 1.8 mm, width 25 mm, length 25 mm). The fireproof materials of the predetermined size were placed on the bottom surface of a stainless steel plate (98 mm square, thickness 0.3 mm) and fed into an electric furnace set at 160°C. The temperature was increased to 400°C at a rate of 5°C/min, and the fireproof materials were removed at 300°C and 400°C, and the expansion ratios at 300°C and 400°C were measured.
The expansion ratio at 300°C is "thickness of the fireproof material at 300°C/thickness of the fireproof material before heating", and the expansion ratio at 400°C is "thickness of the fireproof material at 400°C/thickness of the fireproof material before heating".
The later stage expansion property was evaluated by the following formula (I). The higher the value of formula (I), the better the later stage expansion property is judged to be.
Formula (I) (Expansion ratio at 400°C)/(Expansion ratio at 300°C)
The evaluation was based on the following criteria.
A: The value of formula (I) is 1.7 or more. B: The value of formula (I) is 1.5 or more and less than 1.7. C: The value of formula (I) is 1.2 or more and less than 1.5. D: The value of formula (I) is less than 1.2.

(II) Expansion Pressure The expansion pressure was measured by the following procedure.
(1) The fireproof materials of each of the examples and comparative examples were cut to a predetermined size (thickness 1.8 mm, width 25 mm, length 25 mm).
(2) A hot plate and a force gauge ("ZTA-500N" manufactured by Makita Corporation) were placed 1.2 cm away from the surface of the hot plate. A plate-shaped jig with a diameter of 1.6 cm (area of 2 cm ² ) was used as the jig.
(3) The surface of the hot plate was heated to 500° C., the above-mentioned sheet-like fireproof material was placed on the surface of the hot plate, and a ceramic plate (made of calcium silicate, thickness 2 mm, width 30 mm, length 30 mm) was further placed on the fireproof material.
(4) The above fireproof material was heated on a hot plate at 500° C. for 250 seconds, and the maximum stress measured with a force gauge was divided by the area of the jig to obtain the expansion pressure.

(III) Expansion Ratio The expansion ratio was determined by cutting the refractory material of each Example and Comparative Example to a predetermined size (thickness 1.8 mm, width 25 mm, length 25 mm). The refractory material of the predetermined size was placed on the bottom surface of a stainless steel plate (98 mm square, thickness 0.3 mm), fed into an electric furnace, and heated at 600° C. for 30 minutes. The thickness of the refractory material after heating was divided by the thickness of the refractory material before heating to determine the expansion ratio.

(IV) Fire Resistance Time A door member for evaluating fire resistance time was prepared, which was made of a calcium silicate board (manufactured by Nippon Insulation Co., Ltd.) and a door frame. A gap of 1 cm was provided between the side of the door of the door member for evaluating fire resistance time and the door frame. A fireproof material (thickness 1.8 mm, width 25 mm, length 1000 mm) of each example and comparative example cut to a predetermined size was attached to the side of the door. Then, the fireproof material was heated in a fireproof furnace according to the standard heating curve of ISO834, and the time until the fireproof material peeled off was measured. The longer the time until the fireproof material peeled off, the more excellent the fire resistance of the fireproof material. Evaluation was performed according to the following criteria: S: Time until peeling off is 110 minutes or more; A: Time until peeling off is 105 minutes or more but less than 110 minutes; B: Time until peeling off is 100 minutes or more but less than 105 minutes; C: Time until peeling off is 95 minutes or more but less than 100 minutes; D: Time until peeling off is less than 95 minutes.

(VI) Moldability When kneading with rolls, if the material is too hard to flow or too soft to flow and cannot maintain its shape, the yield will decrease. Moldability was judged as the yield of the material that could be taken out in sheet form after kneading, as shown below.
A: 90% or more B: 70% or more but less than 90% C: 50% or more but less than 70% D: Less than 50%

(VII) Expansion Start Temperature of Thermally Expandable Graphite In a rheometer ("Discovery HR-2", manufactured by TA Instruments), 0.5 g of a sample of thermally expandable graphite was placed on the sample stage and wrapped in aluminum foil to prevent the powder from falling off. The sample was grounded with a 25 mmφ cone plate until the load became 0 [N]. From that state, the sample was heated at a constant heating rate (10°C/min) from a set temperature of 50°C using a Peltier heater, and the point when the load became 0.1 N was taken as the expansion start temperature.

(VIII) Endothermic onset temperature of endothermic agent Measured using a thermogravimetric differential thermal analyzer (TG-DTA). The measurement conditions were: from room temperature to 1000° C., a heating rate of 4° C./min, and an endothermic agent weight of 10 mg. The temperature at which the weight started to decrease from the obtained TG curve was determined as the endothermic onset temperature.

The various components used in each of the examples and comparative examples are as follows.
(Thermoplastic resin)
1. Ethylene-vinyl acetate copolymer, EVA (1) "EV180" manufactured by Dow Mitsui Polychemical Co., Ltd.
MFR at 190 ° C: 0.2 g / 10 min
Vinyl acetate content: 33% by mass
・EVA (2) "EV260" manufactured by Dow Polychemicals Co., Ltd.
MFR at 190 ° C: 6.0 g / 10 min
Vinyl acetate content: 28% by mass
-EVA (3) "V422" manufactured by Dow Polychemicals, Inc.
MFR at 190 ° C: 0.9 g / 10 min
Vinyl acetate content: 20% by mass
・EVM (1) "Revaprene 800" manufactured by Lanxus
Mooney viscosity ML(1+4) at 100°C: 27
Vinyl acetate content: 80% by mass

2. Polyvinyl acetate resin: Polyvinyl acetate (1) "VINNAPAS 4FS" manufactured by Tomoe Chemical Industry Co., Ltd.
Weight average molecular weight: 300,000 g/mol
Polyvinyl acetate (2) "VINNAPAS 25FS" manufactured by Tomoe Chemical Industry Co., Ltd.
Weight average molecular weight: 500,000 g/mol

3. Chloroprene rubber, Chloroprene 1: Skyprene TSR-56, manufactured by Tosoh Corporation
Mooney viscosity ML(1+4) at 100°C: 70
・Chloroprene 2 "Skyprene 640" manufactured by Tosoh Corporation
Mooney viscosity ML(1+4) at 100°C: 85

4. Polyacrylonitrile resin: "P-90H" manufactured by Shaoxing Gimel Advanced Materials Technology Co., Ltd.
5. Polycarbonate resin: "Toughlon" manufactured by Idemitsu Kosan Co., Ltd.
6. Phenolic resin - Novolac type phenolic resin "PR-50235" manufactured by Sumitomo Bakelite Co., Ltd.

(Thermal Expandable Graphite)
・Thermal expandable graphite: Fuji Graphite Co., Ltd. "EXP-50S120K", expansion start temperature 120℃
- Thermally expandable graphite: Fuji Graphite Co., Ltd. "EXP50S160", expansion start temperature 160℃
- Thermally expandable graphite: ADT351, thermal expansion starting temperature 170°C
・Thermal expandable graphite: Fuji Graphite Co., Ltd. "EXP50HO", expansion start temperature 200℃

(Thermal absorption agent)
Calcium sulfate, manufactured by Taihei Chemical Co., Ltd., endothermic start temperature 160°C, endothermic amount 700 J/g
Aluminum hydroxide, "BF013" manufactured by Nippon Light Metal Co., Ltd., endothermic start temperature 200°C, endothermic amount 900 J/g
Calcium hydroxide, "CAOH-2" manufactured by Suzuki Kogyo Co., Ltd., endothermic onset temperature 421°C, endothermic amount 980 J/g

(Flame retardant)
・Aluminum phosphite "APA100" manufactured by Taihei Chemical Industry Co., Ltd.

(Liquid plasticizer)
・Adipic acid ether ester type "Adeka Cizer RS-107" manufactured by ADEKA Corporation

(Examples 1 to 33, Comparative Examples 1 to 6)
Resin, thermally expandable graphite, heat absorbing agent, flame retardant, and plasticizer were put into a roll and kneaded at 120° C. for 5 minutes according to the formulations shown in Tables 1 to 4 to obtain a fire-resistant resin composition. The obtained fire-resistant resin composition was press-molded at 100° C. for 3 minutes to obtain a sheet-shaped fire-resistant material having a thickness of 1.8 mm. The evaluation results are shown in Table 1.

As shown in the above examples, it was found that the fireproof material of the present invention, which contains the expansion start retarder, heat expandable graphite or heat endothermic agent, has excellent late expansion properties, a long fire resistance time, and excellent fire resistance. In contrast, it was found that the fireproof materials of each comparative example, which do not contain the expansion start retarder, have poor late expansion properties, a short fire resistance time, and poor fire resistance.

Claims (7)

The composition contains a resin, thermally expandable graphite A, and an expansion start retarder that delays the expansion start of the thermally expandable graphite A,
the resin comprises an ethylene-vinyl acetate copolymer;
The ethylene-vinyl acetate copolymer is an ethylene-vinyl acetate copolymer containing a high Vac component having a vinyl acetate content of 20% by mass or more,
A thermally expandable fire-resistant material (excluding those containing zinc oxide) , wherein the expansion initiation retarder is thermally expandable graphite B having a lower expansion initiation temperature than the thermally expandable graphite A. 2. The thermally expandable refractory material according to claim 1, wherein the thermal expansion start temperature of the thermally expandable graphite A is TA and the thermal expansion start temperature of the thermally expandable graphite B is TB, and the difference between TA and TB (TA-TB) is 40°C or more. The thermally expandable fire-resistant material according to claim 1 or 2, in which the ratio of the content of thermally expandable graphite A to the content of thermally expandable graphite B (content of thermally expandable graphite A/content of thermally expandable graphite B) is 10/90 to 90/10. The thermally expandable fire-resistant material according to any one of claims 1 to 3, wherein the total thermally expandable graphite content is 20 to 500 parts by mass per 100 parts by mass of resin. The thermally expandable fire-resistant material according to any one of claims 1 to 4, further comprising a flame retardant. The thermally expandable fire-resistant material according to any one of claims 1 to 5 , wherein the ethylene-vinyl acetate copolymer contains a low MFR component having a melt flow rate (MFR) at 190°C of 8.0 g/10 min or less. The thermally expandable fireproof material according to any one of claims 1 to 6 , further comprising a crosslinking agent.