JP2003293296A - Flame-retarded paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide flame-retarded paper which has both excellent environmental compatibility and high flame retardancy. <P>SOLUTION: This flame-retarded paper prepared by disposing a coating layer containing a water-insoluble powdery flame retardant on flame-retarded paper base paper having flame retardancy of an oxygen index of 18 to 24 defined by JIS K7201 is characterized in that the oxygen index is ≥30. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant paper used for electric / electronic parts and the like, and in particular, JIS K7201 despite not using antimony or halogen compounds.
The present invention relates to a flame-retardant paper having a high degree of flame retardancy with an oxygen index of 30 or more.

[0002]

2. Description of the Related Art As a general method for producing flame-retardant paper, a paper base material containing wood pulp as a main component is impregnated with a liquid flame-retardant treating agent, and a powder flame-retardant agent is used as a solvent. A method of melting and coating in the same manner, a method of incorporating a powdery flame retardant into a paper as a filler, and the like are known. In particular, antimony, halogen compounds and the like have been conventionally used for applications requiring a high degree of flame retardancy, but it has become impossible to use the above flame retardants due to the recent heightened awareness of environmental problems. Therefore, in recent years, the use of phosphorus compounds, inorganic compounds, and the like has become widespread (for example, Japanese Patent Laid-Open Publication No. H6-6).
-287892, Japanese Patent Laid-Open No. 9-158092).

[0003]

However, since phosphorus compounds and inorganic compounds, which are becoming mainstream at present, have lower flame retardance than antimony trioxide, halogen compounds, etc.,
Even if it is attempted to use it as a flame-retardant paper used for applications that require a high degree of flame retardancy, the amount of flame-retardant added to the paper inevitably increases with conventional technology, which complicates the manufacturing process. However, there is a drawback that it is difficult to manufacture. Furthermore, as the amount of flame retardant used increases, the paper strength and insulating properties decrease, and when phosphorus compounds are added internally in the papermaking process, the phosphorus concentration in the wastewater increases There was a drawback that the load increased.

Therefore, the inventors of the present invention have conducted extensive studies to solve the above-mentioned drawbacks, and as a result, provided a coating layer containing a water-insoluble powdery flame retardant as a pigment on the flame-retardant paper. The inventors have found that it is possible to obtain a flame-retardant paper having a high flame retardancy that cannot be obtained with these flame retardants, that is, a flame-retardant paper having an oxygen index of 30 or more defined in JIS K7201 and arrived at the present invention. Therefore, a first object of the present invention is to provide a flame-retardant paper which is excellent in environmental compatibility and has high flame retardancy. A second object of the present invention is to provide a flame-retardant paper which has environmental compatibility and high flame retardancy and is also excellent in electrical insulation.

[0005]

Means for Solving the Problems The above-mentioned various objects of the present invention are as follows: the oxygen index defined by JIS K7201 is 18 to
A flame-retardant paper comprising a flame-retardant base paper having a flame-retardant property of 24 and a coating layer containing a water-insoluble powdery flame retardant, the oxygen index of which is 30 or more. Achieved by flame retardant paper. As the flame retardant, it is preferable to use a flame retardant other than antimony or a halogen compound, and it is preferable to use a flame retardant other than a hydrated compound in order to improve the insulating property. As the flame retardant, it is preferable to use at least one flame retardant selected from melamine phosphate, melamine polyphosphate, melamine sulfate, melamine metaphosphate, and melamine-coated ammonium polyphosphate.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS When a flame retardant is internally added as in the prior art, the flame retardant is uniformly distributed in the paper layer. Therefore, a large amount of the flame retardant should be added in order to impart high flame retardancy. Must be added internally. On the other hand, in the present invention, since the coating layer using the powdery flame retardant as a pigment is provided, the flame retardant is present in the surface layer close to the ignition source, so it is effective even if the absolute amount of the flame retardant is small. It is possible to impart flame retardancy to. The present invention will be described below.
This will be specifically described.

The flame-retardant paper of the present invention comprises a flame-retardant base paper having an oxygen index of 18 to 24 and a coating layer containing a water-insoluble flame retardant, and an oxygen index of 30 or more. is there. The oxygen index indicates the oxygen concentration capable of continuous combustion, and is defined in JIS K7201. The flame retardant used in the coating layer of the flame-retardant paper of the present invention is preferably a compound containing no antimony or halogen so as not to cause environmental problems, and is insoluble in water from the viewpoint of reducing drainage load. Must be In addition, hydrated metal compounds such as hydrated aluminum hydroxide and hydrated magnesium hydroxide generate water when heated, which is not preferable for applications requiring electrical insulation. Preferred as the flame retardant used in the present invention is melamine phosphate,
Examples thereof include phosphorus compounds such as melamine metaphosphate, melamine polyphosphate, and ammonium melamine-coated polyphosphate, melamine sulfate, and silicone compounds. Different flame retardants may be used together, or flame retardant aids may be used together.

In the present invention, such a water-insoluble flame retardant is used as a pigment to prepare a coating liquid, which is then coated on the surface of a conventional flame-retardant base paper (oxygen index 18-24). Get the paper. The amount of flame retardant applied is 5-40 g / m per side.
It is preferably in the range of ² . If the coating amount is less than 5 g / m ² , the base paper surface cannot be completely covered,
It is not possible to obtain sufficient flame retardancy. Coating amount is 40g /
Even if it exceeds m ² , the improvement in flame retardancy reaches a ceiling, so further coating is useless.

As the binder used in the coating liquid,
Styrene / butadiene type resin, styrene / acrylic type resin, acrylic type resin, urethane type resin, vinyl acetate type resin, polyvinyl alcohol, starch, etc. which are used for general coating materials can be used. Above all, it is particularly preferable to use an insulating binder. By using an insulating binder, JIS C2
In the dielectric breakdown test specified in 111, 1.5 kv
It is possible to use it as a flame-retardant insulating paper having an electric insulating property of / mm or more.

The blending ratio of the flame retardant and the binder is not particularly limited, but due to problems such as paper powder and surface strength,
It is necessary to have a minimum amount of binder that can hold the flame retardant in the coating layer. Depending on the flame retardancy of the flame-retardant paper used as the base paper, the amount of the flame-retardant is 50 to 100 parts by weight of the binder.
It is preferable to mix it so as to be 2,000 parts by weight. Furthermore, a dispersant, a defoaming agent, a water resistance agent, a viscosity modifier, a release agent, etc. can be appropriately added to the coating liquid, if necessary. The coating method in that case is not particularly limited, by the coater such as an air knife method, a bar blade method, a blade method, and a gate roll method, the both sides of the base paper are coated with the coating liquid of the present invention. Flame-retardant paper can be obtained.

In order to obtain a high degree of flame retardancy with an oxygen index of 30 or more, the flame-retardant paper base paper used in the present invention has an oxygen index of 18-.
It is necessary to have a flame retardancy of 24. When the oxygen index of the flame-retardant paper base paper is less than 18, even if both sides of the base paper are coated with a coating layer containing a flame retardant, the base paper in the layers between the base paper easily burns and the flame may spread from there. . On the other hand, using a base paper having an oxygen index of more than 24 is different from the purpose of the present invention in that the amount of flame retardant used is reduced because such a base paper internally adds a large amount of flame retardant. Become.

The flame-retardant paper base paper used in the present invention is produced by wet-making a paper-making raw material mainly composed of wood pulp, and further adding and dispersing a powdery flame retardant therein. The wood pulp used in the present invention is a softwood kraft pulp, a hardwood kraft pulp, a chemical pulp such as a sulfite pulp, a stone grind pulp, a mechanical pulp such as a thermomechanical pulp, a newspaper, a coated paper, a recycled pulp obtained from a high-quality paper or the like. It is possible to appropriately select and blend from general papermaking pulp such as. If necessary, non-wood pulp such as kenaf, bamboo and hemp, and non-cellulosic fibers such as glass fibers and polyester fibers can be blended.

In the production of flame-retardant paper base paper, at least one flame retardant selected from melamine phosphate, melamine polyphosphate, melamine sulfate, melamine-coated ammonium polyphosphate, etc. is added to these pulp raw materials for papermaking. ,
It is added so that the content in the paper is 10% by weight or more and less than 50% by weight, preferably 15% by weight or more and less than 30% by weight. A commercial item can be used as these flame retardants. For example, MPP is used as the melamine polyphosphate, Apinone 901 is used as the melamine sulfate from Sanwa Chemical Co., Ltd., and the melamine-coated ammonium polyphosphate is TERAGE C-60, C-70, and C-80 as Chisso Co., Ltd. Better sold. These flame retardants may be used alone or in combination of two or more.
When the content of the flame retardant in the paper is less than 10%, sufficient flame retardancy cannot be obtained and the oxygen index cannot be satisfied.
Further, even if the content ratio of the flame retardant in the paper is 50% or more, the flame retardant effect reaches the ceiling. Therefore, it is meaningless from an economical point of view to blend more than necessary a flame retardant, which is generally more expensive than papermaking raw materials.

In making the flame-retardant insulating paper of the present invention,
To the extent that it does not affect the flammability and insulation properties,
Retention improver, paper strength improver, fixing agent, defoaming agent, dye, etc.
It is possible to add internal additives. Also, talc,
Internal filler such as kaolin, calcium carbonate, titanium dioxide
It is also possible to add. The flame retardant insulating paper of the present invention
The amount is 50g / m according to the application^TwoTo 500 g / m ^Two
It is possible to design appropriately up to a degree. Also in the density
Even with, 0.7g / cm depending on the application^ThreeTo 1.2
g / cm^ThreeIt is possible to design appropriately up to a degree.

[0015]

EFFECT OF THE INVENTION The flame-retardant paper of the present invention is imparted with a high degree of flame-retardancy by blending a water-insoluble powdery flame retardant as a pigment in a coating liquid and coating it on the flame-retardant paper. Therefore, high flame retardancy with an oxygen index of 30 or more can be easily obtained. Also,
Since it does not contain substances that may adversely affect the environment, such as antimony and halogen compounds as flame retardants, the load on the environment is small.

[0016]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. In addition, the evaluation of the flame-retardant paper of Examples and Comparative Examples,
The following test was performed. The results are as shown in Table 1. -Oxygen index: According to JIS K7201. -Dielectric breakdown test: A dielectric breakdown test was performed according to JIS C2111.

Embodiment 1. Containing 20 parts of melamine polyphosphate (trade name: MPP, manufactured by Sanwa Chemical Co., Ltd.) per 100 parts of softwood kraft pulp (NBKP) having a freeness of 400 ml (Canadian standard method), the basis weight is 100 g / m. ^Two
With 100 parts of melamine polyphosphate (trade name: MPP, manufactured by Sanwa Chemical Co., Ltd.)
And styrene-butadiene resin (trade name: ST550
2, 100 parts by Nippon Zeon Co., Ltd., a dispersant (trade name:
Aron T-40, manufactured by Toagosei Co., Ltd. (0.3 parts) was mixed to a coating solution of 50 g / m ² on both sides to obtain a flame-retardant paper having a basis weight of 150 g / m ^2. It was

Example 2. Containing 25 parts of melamine polyphosphate (trade name: MPP, manufactured by Sanwa Chemical Co., Ltd.) per 100 parts of NBKP having a freeness of 400 ml (Canadian standard method), a basis weight of 100 g / m ² and an oxygen index of 24 100 parts of melamine-coated ammonium polyphosphate (trade name: Terarge C60, manufactured by Chisso Corporation) on flame-retardant paper base paper,
Styrene / acrylic resin (trade name: PDX7324,
Johnson Polymer Co., Ltd. 60 parts, Dispersant (trade name: Aron T-40, Toagosei Co., Ltd.) 0.3 part, and polyvinyl alcohol (trade name: PVA103,
50 parts on both sides with a coating liquid mixed with 10 parts by Kuraray Co., Ltd.
was coated so as to g / ^{m 2,} a basis weight to obtain a flame燃紙of 150 g / ^{m 2.}

Example 3. Contains 100 parts of NBKP having a freeness of 400 ml (Canadian standard method) and 15 parts of melamine-coated ammonium polyphosphate (trade name: Terarge C60, manufactured by Chisso Co., Ltd.), a basis weight of 100 g / m ² and an oxygen index of 22. 100 parts of melamine-coated ammonium polyphosphate (same as above), nitrogen-based flame retardant aid (trade name: STF100, manufactured by Shikoku Kasei Co., Ltd.), and polyvinyl alcohol (trade name: PVA117, (stock)
60g / m on both sides with a coating liquid mixed with 10 parts by Kuraray
^It was coated so as to have a weight of ² to obtain a flame-retardant paper having a basis weight of 160 g / m ² .

Comparative Example 1. A melamine polyphosphate (trade name: M) on high-quality paper (oxygen index 14) having a basis weight of 100 g / m ²
100 parts of PP, manufactured by Sanwa Chemical Co., Ltd., 100 parts of styrene-butadiene resin (trade name: ST5502, manufactured by Nippon Zeon Co., Ltd.), and dispersant (trade name: Aron T)
-40, manufactured by Toagosei Co., Ltd.) was mixed to a coating solution of 60 g / m ² on both sides, and the basis weight was 16
A flame-retardant paper of 0 g / m ² was obtained.

Comparative Example 2. Containing 15 parts of melamine polyphosphate (trade name: MPP, manufactured by Sanwa Chemical Co., Ltd.) per 100 parts of NBKP having a freeness of 400 ml (Canadian standard method), a basis weight of 100 g / m ² and an oxygen index of 16 are difficult. 100 parts of melamine polyphosphate (trade name: MPP, manufactured by Sanwa Chemical), 100 parts of styrene-butadiene resin (trade name: ST5502, manufactured by Zeon Corporation), and a dispersant (trade name: Aron T-40, Toagosei Co., Ltd.
A coating liquid containing 0.3 parts by weight was applied so as to have a weight of 60 g / m ² on both sides to obtain a flame-retardant paper having a basis weight of 160 g / m ² .

Comparative Example 3. Flame-retardant paper having a basis weight of 160 g / m ² containing 40 parts of melamine polyphosphate (trade name: MPP, manufactured by Sanwa Chemical Co., Ltd.) per 100 parts of NBKP having a freeness of 400 ml (Canadian standard method). Obtained by wet papermaking.

[Table 1] As shown in Table 1, in the case of the flame-retardant papers of Examples 1 to 3 of the present invention, it was demonstrated that all of them have excellent flame retardancy with an oxygen index of 30 or more. In particular, in the case of Examples 1 and 2 in which the styrene resin was used as the binder of the coating layer, it had an excellent insulating property of 1.5 kV / mm or more. On the other hand, in the case of Comparative Examples 1 and 2 in which the flame retardancy of the base paper is low, the flame retardancy may be considerably low even though a larger amount of the flame retardant is applied than in the case of Example 1. confirmed. It is considered that this is because, as described above, the flame spreads from the base paper portion due to the low flame retardancy of the base paper. That is, it means that even if a large amount of flame retardant is used, highly flame-retardant paper cannot be obtained unless the base paper has a certain degree of flame retardancy. Further, in the case of the flame-retardant paper internally added with the flame-retardant of Comparative Example 3, it was confirmed that the flame-retardant property was inferior even though the content of the flame-retardant was almost the same as that of Example 1. It was

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4H028 AA07 AA30 BA02 BA04                 4L055 AA02 AC06 AG06 AG09 AG39                       AH26 BE08 EA19 EA34 FA19                       GA44

Claims (4)

[Claims] 1. A flame-retardant paper comprising a flame-retardant paper base paper having an oxygen index of 18 to 24 defined by JIS K7201 and having a coating layer containing a water-insoluble powdery flame retardant. A flame-retardant paper having an oxygen index of 30 or more. 2. The flame-retardant paper according to claim 1, wherein the flame-retardant is a water-insoluble flame-retardant containing no halogen other than a hydrated metal compound. 3. The flame retardant is at least one flame retardant selected from melamine phosphate, melamine polyphosphate, melamine sulfate, melamine metaphosphate, and melamine-coated ammonium polyphosphate. Flame-retardant paper. 4. An insulating property of 1.5 kV / mm or more in a dielectric breakdown test of JIS C2111.
The flame-retardant paper described in any one of 3 to 3.