JPS58219920A - Hygroscopic material - Google Patents

Abstract

PURPOSE:To provide a hygroscopic material enhnaced in processability and durability to hygroscopic salts during use, obtained by supporting hygroscopic salts by a flame resistant fiber obtained by the oxidation of an acrylonitrile fiber. CONSTITUTION:An acrylonitrile fiber is subjected to heat treatment in an oxidative atmosphere to obtain a flame resistant fiber with a bonded oxygen amount of 7-20wt%. This flame resistant fiber is used as a carrier to support hygroscopic salts such as lithium chloride, lithium bromide or calcium chloride in an amount of 10-75%. This supported fiber is introduced into a column in a tow form or directly in a staple fiber form to fill the same or processed into a paper like form, a felt, a spun yarn or fabric to form a hygroscopic material. This hygroscopic material is high in hygroscopicity and can be prepared in low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hygroscopic material carrying hygroscopic salts, and more particularly to a hygroscopic material carrying a hygroscopic agent using flame-resistant fibers derived from acrylonitrile fibers as a carrier. It is.

Hitherto, as fibrous hygroscopic materials for the purpose of dehumidification, there have been known hygroscopic materials in which hygroscopic salts such as lithium bromide and lithium chloride are supported on asbestos or fibrous activated carbon as carriers (Japanese Patent Application Laid-Open No. 53-123547.) However, asbestos as a carrier for this moisture-absorbing material is heat-treated to increase its hydrophilicity before supporting the moisture-absorbing material, but asbestos itself has high strength but low elongation. It is fragile, and its dust is not good for human health. Further, although fibrous activated carbon has a high loading capacity, the fibers themselves are fragile and have poor processability, and the manufacturing process is long, resulting in high manufacturing costs and low yields.

As a result of research on such problems, the present inventors found that
By using acrylonitrile fibers obtained by oxidation treatment as a flame-retardant carrier, the amount of oxygen bonded from the acrylonitrile fibers is 1 It is a hygroscopic material made by carrying 10 to 15% by weight of hygroscopic class M on 20% by weight of flame-resistant fiber.

This hygroscopic material has excellent processability and also has superior durability against hygroscopic salts during use.

The acrylonitrile fiber used in the present invention includes
The fiber is obtained from a polymer or copolymer containing at least 85% by weight of acrylonitrile, preferably 90 to 98% by weight. In this case, the comonomers include acrylic acid, methacrylic acid, allylsulfonic acid or salts thereof, esters, acid chlorides, acid amides, n-substituted m conductors of vinylamide, vinyl chloride, vinylidene chloride, α-chloroacrylonitrile. , vinylpyridines, vinylbenzine sulfonic acid, vinylsulfonic acid and its alkaline earth metal salts. Further, as the acrylonitrile fiber, fibers made from modified polymers of acrylonitrile polymers, and mixtures of acrylonitrile polymers and copolymers are also used.

The fineness of the acrylonitrile fiber is not particularly limited, but preferably 0.5 to 15 d1, particularly 1.5 to 5 d. When it is thinner than 0.5 d, the fiber strength is low and the fiber is likely to be cut. On the other hand, when it is thicker than 15 d, the chemical resistance of the fiber becomes low.

Flame-resistant fibers derived from acrylonitrile fibers are
Obtained by heat treating acrylonitrile fibers in an oxidizing atmosphere. Air, oxygen,
Single gases such as hydrogen chloride and sulfur dioxide gas, mixed gases, or mixed gases of these and inert gases are used.
Mainly, air and a mixed gas of air and nitrogen are optimal from the point of view of economy and process stability.

The oxygen concentration of the oxidizing atmosphere in the oxidation treatment is 0.2~
A range of 35% by volume is most effective. It is preferable that the oxidation treatment is carried out in two stages: the first stage oxidation is carried out in a medium with an oxygen concentration of 20 to 35% by volume, and the second stage oxidation is carried out in a medium with an oxygen concentration of 0.5 to 9%. Oxidation is carried out at 200-400°C, and the optimum temperature varies depending on the amount and type of comonomer constituting the acrylonitrile fiber, but the optimum temperature is 225-33°C.
It is in the range of 0°C. At that time, it is preferable that the applied tension be such that the shrinkage at the oxidation temperature is 40 to 90% of the free shrinkage rate at that temperature during the oxidation treatment.

If this value is less than 40%, it will be easy to cut when flame resistant, and
If it exceeds 0%, processability during the production of hygroscopic materials will deteriorate.

The oxidation treatment reduces the amount of oxygen bonding in acrylonitrile fibers to 7.
It is necessary to carry out the process until the concentration is ~20% by weight, and the time required for this varies depending on the copolymer composition of the acrylonitrile fiber, the degree of oxidation treatment, etc., but is 0.5 to 30 hours, especially 1 to 20% by weight.
It is 10 hours. If the amount of oxygen bonding is less than 1% by weight, it is not preferable because the durability of the fiber against the moisture absorbent becomes poor when absorbing moisture, and the processability and yield during the production of the long material decreases.

Such flame-resistant fibers have a tensile strength r! As IL1 hygroscopic salts, lithium chloride, lithium bromide, calcium chloride, etc. are used.

In order to support the hygroscopic salts on the flame-retardant fibers, the flame-retardant fibers as a carrier are immersed in an aqueous solution of hygroscopic salts or a solution of methyl alcohol, edyl alcohol, or the like; A solution of the hygroscopic salts is passed through a molded body filled with the hygroscopic salts, adsorbed, and supported by drying.

The supported amount of hygroscopic salts is 10 to 15% by weight, and 10 to 15% by weight.
If it is less than 1%, the amount of moisture absorbed is too small to be used in practical use, and if it exceeds 15%, the amount of moisture absorbed is too small.
This is not preferable because the material tends to become sticky, resulting in poor shape retention and handling properties.

The moisture-absorbing material according to the present invention may be in the form of a tow or short fibers packed in a column, processed into paper, felt, spun yarn, woven fabric, etc., and any of them can be used.

The flame-resistant fibers derived from acrylonitrile fibers in the present invention have excellent processability, and in particular, have a higher knot elongation than asbestos, fibrous activated carbon, etc., so they can be made into felt by needle punching or using tow. It can be used as a carrier in the form of a spun yarn by tow spinning or the like, or in the form of a woven fabric.

Supporting of hygroscopic salts is carried out by flame-retardant fibers. It is necessary to do it after making it into a form.

This is due to the requirements to prevent hygroscopic salts from falling off and to prevent rust from spinning machines, looms, etc. Furthermore, when the fibers are to carry hygroscopic salts in the steps after spinning, it is preferable to remove the spinning oil agent in advance. This is because the spinning oil is usually water repellent. It is also desirable to carry hygroscopic salts after spinning using a hydrophilic spinning oil or applying a hydrophilic surfactant.

Hydrophilic spinning oil and surfactant have 8 to 17 carbon atoms.
Ester, ether, amide compounds of reaction products of aliphatic hydrocarbons or aliphatic hydrocarbons having 8 to 11 carbon atoms and aromatic compounds, and reaction products of these compounds with polyethylene oxide, sulfonic acid, phosphoric acid compounds, Examples include those having good solubility and dispersibility in water.

Specific examples thereof include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene alkylamine, alkylbenzene sulfonate, and alkylbenpine sulfone sodium salt. As such, for example, a reaction product with polyethylene oxide is preferably 1-11815 or more. On the other hand, as a reaction product with sulfonic acid or phosphoric acid, a reaction product with an aliphatic hydrocarbon having 8 to 12 carbon atoms is preferable.

The flame-resistant fiber in the present invention has an oxygen bonding amount of 1 to 20% by weight. When the amount of oxygen binding is within this range, the amount supported is large and the yield during spinning is high. If it is less than 7% by weight, the supported amount will be small, and if it exceeds 20% by weight, the yield will be low.

This is clear from the results in Table 1 below.

Table 1 shows the support m when a 100% spun yarn Nishiki count 11 obtained by cotton spinning of flame-retardant II miscellaneous material was used as a carrier, and when this was immersed in an ethanol solution containing 3% lithium chloride and taken out, and This figure shows the results of investigating the yield during cotton spinning for various amounts of oxygen binding.

Table 1 [Oxygen bond support in flame-retardant fibers, yield during spinning] The yield during spinning is shown as a guideline for fiber brittleness, and processing other than spinning, such as needle A similar tendency can be seen in processes such as felting by punching and paper making.

Next, the present invention will be explained with reference to examples.

Example 1 An acrylonitrile fiber made from a copolymer of 97% by weight of acrylonitrile component and 3% by weight of methyl acrylate component, and was composed of a single fiber having a thickness of 1.5 denier (d). 500,000d tow for 250”030 minutes then 26
5℃ 20 minutes, then 280℃ 15 minutes tension cuff 0mg/
Continuously flame resistant under d. I of the following physical properties! I got miscellaneous.

10- Tensile strength 1.7g/d Tensile elongation 13% Specific gravity 1.489/ell" Oxygen bond 1 13% by weight This flame-resistant fiber and pulp are mixed and paper is made, and the flame-resistant fiber content is 60% by weight. , basis weight 120o/+a', thickness 0.
A 45m5 piece of paper was created. Using the obtained flame-resistant sui-containing paper as a carrier, the concentration of lithium bromide was 3% by weight and 5% by weight.
, 1% by weight of each ethanol solution, taken as is, and dried at 120° C. to obtain three types of moisture absorbing materials.

When the amount of this material supported was investigated, the results shown in Table 2 below were obtained. I instead of flame-resistant fiber! Table 2 shows the supported amount of fibrous activated carbon-containing paper obtained in the same manner as above, as well as of each moisture absorbing material of glass fiber sheet and asbestos sheet. .

10- Table 2 [Lithium bromide (Li Br ) of various moisture absorbing materials
Supported amount) (Note) Supported ff1 (%) is the heaviest ratio of lithium bromide to the total weight.

According to Table 2, the moisture-absorbing material using the flame-retardant i*ett-containing paper of the present invention as a carrier shows an excellent loading m compared to other fibrous activated carbon-containing papers.

Further, when the moisture absorption properties of the obtained moisture absorption material were investigated, the results shown in Table 3 below were obtained. The moisture absorption property was determined by measuring the amount of moisture absorbed when the sample was left in air with a humidity of 65% and saturated.

According to Table Wi3, all the products of the present invention exhibit excellent absorption characteristics. The asbestos sheets shown in Table 2 have a supported amount of lithium bromide of 2% by weight and 5% by weight.
and 1% by weight, the moisture absorption was 5%, 7%, and 10% by weight, respectively, and only extremely low hygroscopicity was known.

\ Patent applicant: Toho Bethlon Shinto Company Representative Patent Attorney, Third Department

Claims (1)

[Claims] Oxygen bonds derived from acrylonitrile fibers 11~
20% by weight of flame-retardant fibers with 10-75ff of hygroscopic salts
l Hygroscopic material with 11% loading