JPH0394808A - Flame-retardant gas filter medium and its production - Google Patents

Abstract

PURPOSE:To obtain an excellent flame-retardant gas filter medium by incorporating a flame-retardant selected from a group consisting of the flame-retardants based on the ammonium polyphosphate, org. phosphorus-nitrogen compd. and phosphoric ester into a polyvinyl acetal-based porous base material. CONSTITUTION:At least one kind of phosphorus-based flame-retardant selected from a group of the flame-retardants based on the ammonium polyphosphate, org. phosphorus-nitrogen compd. and phosphoric ester is incorporated by 10-80wt.% into the gas filter medium consisting of porous polyvinyl acetal-based resin or its processed body to obtain the medium. The medium is excellent in flame retardancy and generates only a small amt. of low toxicity combustion gas even in a fire. Furthermore, the clogging and pressure drop are reduced, a rust preventive effect is produced, and the peripheral equipment is not contaminated because the flame-retardant does not bleed. Consequently, an air filter extremely appropriate for the air conditioning of buildings, etc., is fabricated.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a filter medium for flammable gas used for air conditioning of buildings, etc., and more specifically relates to a filter medium for flame-retardant gas made of a polyvinyl acetal porous material. Concerning filter media and their manufacturing method. (Conventional technology) Air filter devices have been widely used in the electronics industry and precision machinery industry, which require high-purity clean air, as well as in building air conditioning equipment. There are two types of filter media used in this air filter device: inorganic and organic. Whisker. Aggregates of inorganic fibers such as asbestos fibers are used, and organic fibers include nonwoven fabrics of Hewei fibers. A's paper, urethane foam, polyvinyl acetal porous material, etc. are used. Among these, inorganic filter media have the disadvantage that the filter media themselves have low bending strength and tensile strength, are difficult to handle because fibers tend to break or fall off, and are expensive. Furthermore, the carcinogenicity of asbestos has recently become a major issue. On the other hand, in recent years, organic materials have become problematic in terms of their flame retardancy in the event of a fire and the generation of toxic gases during combustion. For this reason, in hand-woven filter media and filter paper, the T1 refueling agent is either mixed with a binder and deposited at the same time during the manufacturing process, or impregnated or coated alone. However, in this case, the H flame retardant is mixed with a binder or attached alone, resulting in a decrease in strength and durability due to the addition of the flame retardant, as well as oozing of the flame retardant, which affects its suitability as a filter medium for gases. rt. ．． There were 'tn points. In general, flame retardants are divided into organic and inorganic types depending on their structure, and organic types are further divided into phosphorus types. It is classified as nitrogen type 1 halogen type. In addition, phosphorus-based flame retardants include phosphoric acid ester-based and polyphosphate-based flame retardants. Phosphorus + halogen type, phosphorus + nitrogen type, reactive phosphorus compound. It is subdivided into organic phosphorus nitrogen compounds, inorganic phosphorus compounds, etc. Here, if the added flame retardant is halogen-based or contains halogen, it will generate harmful halogen-based gas during combustion, which is undesirable.
A method has been proposed in which a non-halogen flame retardant is added internally or externally to a porous body of polyvinyl acetal resin, which is an organic polymer porous body, but when pre-minxing a tII flame retardant internally, a fairly large amount is required. If phosphorus-based flame retardants are not added, sufficient flame retardant effect will not be exhibited.Furthermore, phosphorus-based flame retardants often have properties as plasticizers, and the resulting polyvinyl acetal porous material can be used as a gas filter agent. The problem was that it lacked favorable physical properties. In addition, when a polyvinyl acetal porous material is externally added and impregnated with a flame retardant, there are problems such as damage to surrounding equipment due to oozing, similar to non-woven fabric, and a decrease in the durability of the flame retardant effect. there were. (Problems to be Solved by the Invention) An object of the present invention is to provide a flame-retardant gas filter material that is made of a polyvinyl acetal porous material, has excellent durability in the tiI flame effect, and has low toxicity in the gas generated during combustion. The purpose of this article is to provide a manufacturing method for the same. (Means for solving !I8) The above purpose is to solve polyvinyl acetal (hereinafter referred to as rPVAt).
A gas filter medium made of a porous body of a resin or a processed product thereof, which is referred to as ammonium polyphosphate J1 refueling agent. At least one selected from the group consisting of organophosphorus nitrogen compound flame retardants and phosphate ester flame retardants
This is achieved by a flame-retardant filter medium for gases, which is characterized by applying 10 to 80% by weight of a phosphorus-based flame retardant. Other objects of the invention are achieved by the method described below.

In the present invention, the porous body of PVA t-based resin or its processed product is a raw material made of polyvinyl alcohol (hereinafter referred to as rPVAJ) as a raw material and reacted by adding a catalyst to aldehydes, and has continuous pores. It is a porous body,
The porosity is preferably 80% or more, more preferably 9
It is 0% or more.

The first important point of the present invention lies in the type of flame retardant to be applied. The phosphorus-based flame retardant of the present invention has a rust prevention effect in addition to the III flame effect, and can be applied to the filter medium either internally or externally, or when added externally alone together with a thermosetting resin. Organic phosphorous nitrogen compounds and ammonium polyphosphate do not sublimate at the operating temperature, have almost no bleeding or oozing, and have excellent durability in J1 flame effect, making them suitable for use. I can't see it at all! It had an excellent combustion effect. In addition, when a flame retardant is added internally or externally with a thermosetting resin, phosphate ester-based flame retardants are preferable, and non-halogen phosphate ester-based flame retardants are particularly preferred due to the harmfulness of combustion gas. A fuel is preferred. To externally add the phosphorus-based flame retardant, an appropriate method such as dipping or spraying may be used, it may be simply impregnated onto the PVAt-based porous body, or a mixture of the above-mentioned phosphorus-based flame retardant and thermosetting resin may be used. It may be impregnated and attached, and the application amount is P
Preferably 10 to 8 in weight ratio to VA t-based porous material
0%, more preferably 20-50%. The dosage is 8
If it exceeds 0%, the pressure loss of the filter medium increases and tends to cause clogging, and if it is less than 10%, the flame retardant effect is not sufficient. When a phosphorus-based flame retardant is added internally with a thermosetting resin by an appropriate method such as kneading, the above-mentioned phosphorus-based flame retardant is applied to P.
Weight ratio to VA t-based porous material, preferably 10 to
80%, more preferably 40-60%. If it is less than 10%, the flame retardant effect is insufficient, and if it is more than 80%, the flame retardant effect tends to be saturated or the physical properties as a filter medium tend to be impaired. The second key point of the present invention is that in addition to using a phosphorus flame retardant alone, a phosphate ester flame retardant is added internally or externally together with the thermosetting resin. Examples of the thermosetting resin include urea resin and melamine resin. Resol type phenolic resin, epoxy resin. Urethane resins are used alone or in combination. For internal addition, for example, there is a method of adding a phosphate ester flame retardant and a thermosetting resin to the raw PVA aqueous solution, and a resol type phenolic resin is suitable as the thermosetting resin. Further, when a phosphate ester flame retardant is externally added together with a thermosetting resin by impregnation, etc., urea resin or melamine resin is suitable as the thermosetting resin. If the thermosetting resin is added at the same time as the phosphorus-based W1 flame retardant is internally added, the same flame retardant effect can be obtained even if the amount of the phosphorus-based flame retardant is smaller than when the thermosetting resin is not added. In addition, phosphorus uP. When the agent is externally added together with the thermosetting resin, water resistance and durability are improved compared to when it is not added. Other objects of the present invention are: (1) PVA having a formalization degree of 60 to 86 mol%;
A solution or dispersion of an ammonium polyphosphate flame retardant or an organic phosphorus nitrogen compound til flame retardant having a solid content of 10 to 80% by weight is applied to the T-based porous material, and then dried and fixed, or (+1> formalization degree is 60-86 mol% PV
After applying an aqueous solution of urea resin or melamine resin containing a phosphate ester flame retardant to the At-based porous material, drying it,
Subsequently, the resin is thermally cured, or (1) a resol type phenolic resin and a phosphoric acid ester flame retardant are added to the PVA aqueous solution to form an aqueous solution, and a porous wood, an aldehyde, and a catalyst are further added to acetalize the resin. This is achieved by a method for producing a flame-retardant filter medium for gases, in which after the reaction, the reaction product is washed with water, dried, and then the resin is thermally cured. the above(
In the production method of 1), the degree of formalization of the PVAt-based porous material is preferably 60 to 86 mol%, more preferably 70 to 86 mol%. More preferably, it is 80 to 86 mol%. Highly formalized materials have better water resistance and are suitable as filter media for gases. In the production method (T) above, the PVAt-based porous body is:
An aqueous solution containing one or more completely saponified or partially saponified PVA with an average degree of polymerization of 300 to 2000 is prepared, a porous material is added thereto, and a predetermined amount of aldehydes and a catalyst are added. It can be done uniformly. The reaction product obtained here is a low formalized product having fine continuous pores &lIva with a degree of formalization of 60 to 70 mol%,
This may be used as a PVAt-based porous material, but by applying a mixture of aldehydes and acids again, the degree of formalization is 8.
It is preferable to have a high degree of formalization of 0 mol% or more, and to form a PVAt-based porous body with this high degree of formalization. As the above-mentioned pore-shaped material, for example, various kinds of starches or their swollen products can be used. Examples of aldehydes include formaldehyde. Acetaldehyde. Butyraldehyde or the like is used, and as a catalyst, for example, sulfuric acid, hydrochloric acid, phosphoric acid, etc. are used.

As the phosphorus-based flame retardant in the production method (1) above, preferably an organic phosphorus nitrogen compound, more preferably ammonium polyphosphate is used, and the flame retardant concentration in the aqueous solution is:
Preferably 5-40% by weight, more preferably 15-30%
It is weighted percentage. PVAt in the production method of (n) above
The degree of formalization of the porous body is preferably 40 to 8.
6 mol%, more preferably 70 to 86 mol%,
(1) It can be obtained by the same method as described in the manufacturing method. However, since a thermosetting resin is applied, it does not need to be a highly formalized product, so a formalization reaction of 1 degree is sufficient. ．． The urea resin in the manufacturing method of (II) or
The concentration of the melamine resin in the aqueous solution is preferably 10 to 35% by weight, more preferably 20 to 30% by weight. If the resin concentration is too high, the resulting porous body will be too hard and difficult to bend, and if it is too low, it will tend to lack water resistance as a filter medium. In addition, the flame retardant used in the production method of (ff) is preferably a non-halogen phosphate ester flame retardant due to its reactivity with the tree, and the concentration of the aqueous solution thereof is preferably 10 to 3.
It is 5% by weight, more preferably 20 to 30% by weight. The heat treatment temperature in the manufacturing method of (U) is preferably 11
The temperature is 0 to 150°C, more preferably 120 to 140°C, and the heat treatment time is preferably 3 to 20 hours, more preferably 5 to 15 hours. The flame-retardant porous material in the above-mentioned manufacturing method (Iff) is completely saponified or partially saponified PVAIOO! with an average degree of polymerization of 300 to 2000. Preferably 50 to 16 parts of resol type phenolic resin to 1 part
An aqueous solution containing 0 parts by weight, more preferably 100 to 140 parts by weight, and preferably 30 to 100 parts by weight, more preferably 40 to 80 parts by weight of a non-halogenated phosphate ester flame retardant dissolved therein. was prepared, porous wood was added thereto, the reaction was further carried out for a prescribed amount of 40 hours, the reaction product was washed with water and dried, and 110-150
It can be obtained by processing 3 to 20 o'clock 1" jl? If the amount of resol type phenolic resin added is too large, the resulting porous body will be too hard and cannot be bent. If the amount is too low, the water resistance will be insufficient. (Effect) According to the flame-retardant gas filter medium of the present invention,
When burned in a fire, the smoke emission is low, the combustion gas is low toxicity, there is little increase in pressure loss due to clogging, there is a rust prevention effect, and there is no problem with surrounding equipment due to flame retardant seeping out, so it is suitable for building air conditioning. It is possible to create an air filter device that is extremely suitable for such applications. According to the method of the present invention, the flame retardant effect of the phosphorus flame retardant applied to the porous body of PVAt resin can be utilized extremely effectively, and it has excellent water resistance, durability, and weather resistance, and can be used as a filter medium for gases. A flame-retardant gas filter medium with suitable physical properties can be manufactured. (Example-1) Completely saponified PV with a degree of polymerization of 1400 and a degree of saponification of 99 mol%
A and a polymerization degree of 50o. Partially saponified PVA with a degree of saponification of 88 mol % was mixed at a ratio of 7/3, and 600 parts by weight of an aqueous solution having a concentration of IO weight % was prepared.

To this aqueous solution, 100 parts by weight of 30% by weight potato starch slurry was added as a pore-forming material and mixed with stirring, further 100 parts by weight of 37% formaldehyde aqueous solution was added as a crosslinking agent, and 100 parts by weight of 50% combing acid was added as a catalyst. Add and mix evenly to prepare the reaction solution. Add this adjustment solution to 8
The reaction was carried out at 0'C for 18 hours, and the degree of formalization was 60~
A porous body made of 70 mol% PVAt-based resin. Subsequently, this porous body was placed in a mixture of 20% formalin and 25% sulfuric acid for a secondary reaction at a temperature of 60°C for 150 hours to form a porous PVAL resin with a degree of formalization of 80 to 86 mol%. It is a matter of substance. Then, wash this porous body with water,
The porous body was dried and cut to a thickness of 2 mm, and a 20% aqueous solution of ammonium polyphosphate (trade name: Sumisaf P manufactured by Sumitomo Chemical Co., Ltd.) was applied as a flame retardant to the cut porous body. This was impregnated and dried to obtain a porous filter coated with 50% by weight of flame retardant based on solid content. Next, a flame retardant test was conducted on the porous filter obtained by the following method. (^) Test piece 25 on a wire mesh according to JACA No.11-1977r Filter flammability test method for air purifier
0mm'. 8 0.0 at the center of the 250mm surface. 1.
5 g of hexamine tablets were burned as a fire source, and the maximum carbonization length was measured to be 25 mm or less, passing the evaluation value of 150 mm or less for a flame-retardant filter medium. (B) ASTM D6 3 5 rF
lams. Of I? tgidPlastics
over O. 1 2 7 am (0.0 5
0 in) in ThickJ. Test piece 12 according to
．． 7mmxl27mm held horizontally (width direction 45”) L,
The flame was placed on a Bunsen burner for 30 seconds, and the combustion distance was measured to be 39 mm or less, passing the self-extinguishing evaluation value of 70 mm or less. (Example-2) Partially saponified PVA with a polymerization degree of 1500 and a saponification degree of 95 to 97 mol% and completely saponified PVA with a polymerization degree of 500 and a saponification degree of 99 mol% were mixed at a ratio of 6/4, and the concentration Prepare 800 parts by weight of a 10% by weight aqueous solution. To this aqueous solution, 200 parts by weight of 25% Potato R powder slurry as a pore forming material was added and mixed with stirring, further 150 parts by weight of 37% formaldehyde aqueous solution was added as a crosslinking agent, and 100 parts by weight of 50% sulfuric acid was added as a catalyst. Add and mix evenly to prepare the reaction solution. This prepared solution was reacted at 80°C for 18 hours to form a porous body of PVAt resin. This porous body was washed with water, dried and cut into 2 mm thick pieces, and the cut porous body was treated with 15% dimethylol urea as a thermosetting resin and diptyl hydroxymethyl phosphonate (trade name: CR) as a H reagent. -707 <Daihachi Chemical>) 3
It was immersed in an aqueous solution adjusted to have a concentration of 0% by weight, and after removing the excess aqueous solution, it was dried and subjected to a heat curing reaction at 130° C. for 10 hours to obtain a porous filter medium. Next, a flame retardancy test was conducted on the porous filter medium obtained by the following method.

When tested using method A (flammability test) A-1 (45° micro burner method) of JIS L 1091r flammability test method for textile products, the carbonized area was 30 cm after heating for 1 minute.
The afterflame time was 3 seconds or less, the residual flame time was 5 seconds or less, and the carbonization distance was 20 cm or less, passing Category 3, which is the most excellent flame retardant in the same test method. (Example-3) Degree of polymerization L750. Prepare 500 parts by weight of a 10% by weight aqueous solution of PVA with a degree of saponification of 88 mol%. To this aqueous solution was added 300% of potato starch slurry containing 10% of pores as a pore-forming material.
frf part, and 80 parts by weight of a 70% by weight water-soluble resol type phenolic resin as a thermosetting resin and glycidyl-α-methyl-β-di(but▲xy) as a flame retardant.
Phosphinyl brobinate (trade name: CR-705 <
Daihachi Chemical Co., Ltd.>) was stirred and mixed, 100 parts by weight of 37% formaldehyde aqueous solution was added as a crosslinking agent, and 30 parts by weight of 38% hydrochloric acid was added as a catalyst and mixed uniformly to prepare the reaction solution. do. Add this adjustment solution to 7
The reaction was carried out at 0°C for 18 hours to form a porous body of PVAt-based resin. Then, wash this porous body with water. Dry, 130
After carrying out a thermosetting reaction at ℃ for 18 hours, the material was cut to a thickness of 2 mm to obtain a porous filter medium. Next, a flame retardant test of the obtained porous filter material was conducted using the following method. UL standard (United States Fire Insurance Association) flame retardant test method UL-
According to 94HF-1, when a burner flame was applied to a test piece of a specified shape for 60 seconds and then removed, the afterflame duration was 10.
It passed the criteria of less than 2 seconds and a combustion distance of less than 57.2 mm.

Claims (4)

[Claims] (1) A gas filter medium made of a porous body of polyvinyl acetal resin or a processed product thereof, wherein the gas filter medium is made of an ammonium polyphosphate flame retardant, an organophosphorus nitrogen compound flame retardant, and a phosphate ester flame retardant. At least one phosphorus-based flame retardant selected from the group 10 to 80% by weight
A flame-retardant filter medium for gas, characterized in that it is applied in a weight percent. (2) A solution or dispersion of an ammonium polyphosphate flame retardant or an organic phosphorus nitrogen compound flame retardant with a solid content of 10 to 80% by weight is added to a polyvinyl acetal porous body with a degree of formalization of 60 to 86 mol%. A method for producing a flame-retardant gas filter medium, which comprises drying and fixing the material after application. (3) A solution or dispersion of a urea resin or melamine resin containing a phosphate ester flame retardant is applied to a polyvinyl acetal porous material having a degree of formalization of 40 to 86 mol%, followed by drying. A method for producing a flame-retardant gas filter medium, which comprises thermosetting the resin. (4) A resol-type phenolic resin and a phosphate ester flame retardant are added to an aqueous polyvinyl alcohol solution to form an aqueous solution, and a pore-forming material, aldehydes, and a catalyst are added to carry out an acetalization reaction, and the reaction product is washed with water and dried; A method for producing a flame-retardant gas filter medium, which comprises subsequently thermosetting the resin.