JPS6339934A - Antidusting agent for powdery hydrophilic resin - Google Patents

Abstract

PURPOSE:To obtain the title antidusting agent which controls the dusting of a hydrophilic resin and improves its workability, by mixing an inorganic powder with a specified organic compound. CONSTITUTION:An antidusting agent for a powdery hydrophilic resin is obtained by mixing 20-80wt.% inorganic powder (A) (e.g., diatomaceous earth) of a grain size<=50 mesh with 80-20wt.% at least one organic compound (B) selected from among an oxyethylene ether compound (e.g., trimethylolpropane), a lower polyhydroxy compound (e.g., polyethylene glycol) and its esterified derivatives, each of which has an MW<=25000. Said antidusting agent is mixed with a powdery hydrophilic resin (e.g., polyacrylamide) of a grain size<=8 mesh so that the resulting mixture may contain 0.005-0.5wt% component (B).

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a dusting prevention agent for powdered hydrophilic resins.

More specifically, it relates to a composition for suppressing the dust generation of so-called hydrophilic resin powders such as water bathing polymers such as polyacrylamide and polyethylene oxide, or water absorbing resins such as partially crosslinked sodium polyacrylate. .

[Conventional technology]

Polyacrylamide, polyethylene oxide.

Water-soluble polymers such as polyvinyl alcohol and carboxymethyl cellulose have been prized for use in coagulation and sedimentation treatment of wastewater, thickeners for Japanese paper making, and additives for textile sizing agents and synthetic detergents. On the other hand, the use of water-absorbing resins such as partially cross-linked sodium polyacrylate and partially cross-linked starch-sodium polyacrylate has been expanding in recent years as water-absorbing agents for sanitary napkins and disposable diapers.

By the way, the product form of these water-soluble resins and water-absorbent resins (hereinafter collectively referred to as hydrophilic resins) is mainly powder, but the particle size of powder products is not constant, and some of them include fine powder. is also included. In this case, these powdered hydrophilic resins will be handled.

For example, dust is created when a product is removed from a bag.

This causes problems such as: Specifically, there are sanitary problems such as dust being absorbed into the human body and adhering to the skin, and safety problems such as dust that falls on the floor absorbs moisture and dissolves or swells, making the floor slippery. Therefore, in order to improve the dust generation properties of hydrophilic resins, the first method that can be considered is to remove the fine powder that causes this by sieving (classification), but this method does not improve dust generation π much as expected. . This is thought to be due to the fact that the fine powder is relatively firmly attached to the surface of the larger grains of the hydrophilic resin powder.

In order to solve the problems of such powdery hydrophilic resins, for example, polyacrylamide powder is mixed with preols having an average molecular fi of 6000 or less as a dust generation prevention agent, and furthermore, polyacrylamide powder, which deteriorates when mixed with polyols, is mixed with polyacrylamide powder as a dust prevention agent. In order to improve powder fluidity, compositions have been proposed in which fine particle size inorganic powders are mixed. (Unexamined Japanese Patent Publication No. 52-
121658).

[Problem that the invention seeks to solve]

However, this technique was not sufficiently effective in preventing dust generation from polyacrylamide powder.

[Means for solving problems]

As a result of intensive studies on reducing dust generation in conventional powdered hydrophilic resins, the present inventors mixed a specific organic compound and inorganic powder in advance to create a dust generation prevention agent, and applied this to powdered hydrophilic resins. We have discovered that by mixing, dust generation can be suppressed with a lower amount of organic compound than before, and the workability of producing low dust generation hydrophilic resin can also be improved.
child.

That is, the present invention comprises an inorganic powder (8), an oxyalkylene ether compound (b2), and a lower polyhydroxy compound (b2).
2) and one or more organic compounds (F) (hereinafter abbreviated as organic compounds) selected from K(bs) and its esterification derivative K(bs). Dust prevention agent for hydrophilic resins.

In the present invention, the inorganic powder is diatomaceous earth.

Fused silica, amorphous silica, bentonite, talc.

Examples include industrially easily available water-insoluble inorganic powders such as perlite and alumina, and water-soluble inorganic powders such as sodium chloride, sodium sulfate, sodium phosphate, calcium chloride, and magnesium sulfate.

Among these, water-insoluble inorganic powders are preferred from the viewpoint of effectiveness, and diatomaceous earth is particularly preferred.

The particle size of these inorganic powders is not particularly limited as long as it is finer than the particle size of the powdered hydrophilic resin, but it is preferably 50 mesh or less.

Examples of oxyalkylene ether compounds include oxyalkylene ether monools and oxyalkylene ether polyols. Oxyalkylene ether monools include compounds that have one or more alkylene oxides such as ethylene oxide or propylene oxide added to a compound that has one active hydrogen in one molecule, and have one or more active hydrogen in one molecule. Compounds include aliphatic alcohols of Ci to CIg; phenol, octylphenol, nonylphenol.

Dodecyl phenol, styrenated phenol, and nol
phenol; CtNCpg aliphatic monocarboxylic acid;
Examples include secondary amines containing an alkyl group of C to Cpg.

Oxyalkylene ether polyols include aliphatic polyhydric alcohols such as trimethylolpropane, glycerin, pentaerythritol, and sucrose, and polyfunctional phenolic OHi such as bisphenol A! Alkylene oxide adducts such as compounds; polyethylene glycol,
Examples thereof include polypropylene glycol, polytetramethylene glycol, and a single or copolymer of alkylene oxide such as poly(ethylene oxide-propylene oxide).

Regarding the molecular weight of these [σ]oxyalkylene ether compounds, especially f! Although there is no limit, from the viewpoint of mixing workability with the inorganic powder during the production of the dust prevention agent, it is necessary to use molecules 1 that are liquid at room temperature or that become liquid when heated to 40 to 50°C. Preferably. P
The molecular weight range added by Xf is usually 16,000 or less, preferably toooo or less.

Examples of lower polyhydroxy compounds include aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, and trimethylolpropane, and examples of their esterification agents include diformates, diacetates, and dipropionates of ethylene glycol. Can be mentioned.

These organic compounds may be used alone.

Two or more types may be used in combination.

Among the above organic compounds, oxyalkylene ether monool or oxyalkylene ether polyol, which is obtained by adding ethylene oxide and/or propylene oxide to aliphatic monocarboxylic acid or aliphatic polyhydric alcohol, is preferable.

In addition, other surfactants, mineral oil, silicone oil, alcohol, etc. may be used in combination, if necessary, in amounts that are not dominant to these organic compounds.

The weight ratio of inorganic powder and organic compound is usually 20:80~
80:20 Te, preferably 80 near 0-8G:20
It is.

If the amount of inorganic powder is too small, not only will the entire product become sticky and difficult to handle when producing the dust prevention agent, but also coarse particles will be formed in some areas when mixed with the powdered water absorbent resin. On the other hand, if the amount of inorganic powder is large, there will be no problem as described above, but if the amount of inorganic powder increases.

As the effectiveness of the anti-dusting agent decreases, it is necessary to add more of the anti-dusting agent to the hydrophilic resin powder.

The net 1z of the latter decreases.

Inorganic powders and organic compounds are mixed together.

It is preferable to mix as uniformly as possible. A commercially available powder mixer is used to mix the powder and the organic compound.

For example, any mixing machine such as a V-blender, ribbon blender, Nauta mixer, or ball mill can be used.

In addition, to mix on a small scale, the mixture may be mixed manually using a stirring rod, or may be mixed using a juice mixer.

When mixing an inorganic powder and an organic compound, the two may be added to the mixer in any order, but the inorganic powder may be charged first and the organic compound may be poured in while stirring, or
A method of spraying with an air spray gun or the like is preferred. If the organic compound is solid at room temperature, it can be heated and melted in advance and then mixed with the inorganic powder, or it can be dissolved in a volatile solvent such as methanol, ethanol, or water and mixed with the inorganic powder. Thereafter, the bath agent may be removed by means such as heating and/or reduced pressure.

If the melting point of the solid organic compound is about 40 to 500, the organic compound will melt due to frictional heat while the pulverized solid organic compound is mixed with the inorganic powder.

A homogeneous mixture can be obtained.

The dust prevention agent of the present invention is effective against any synthetic, modified, or natural powdered water-soluble or water-absorbing resin.

Examples of powdered water-soluble resins include polyacrylamide, acrylamide-acrylic acid copolymer or its salt, polysodium acrylate, polymethacryloyloxyethyl trimethylammonium salt, and acrylamide-methacryloyl, which are used as polymer flocculants. Roxyethyltrimethylammonium salt copolymer, polyvinylimidacillin,
Polyvinylpyridine, cationically modified products of polyacrylamide, etc.; polyethylene oxide, polyvinyl alcohol, carboxyvinyl polymer, etc. used as textile glues and thickeners; styrene-maleic acid copolymers used as binders for printing inks, etc. Synthetic polymers such as polymers, their ester derivatives, styrene-(meth)acrylic acid copolymers, (meth)acrylate-(meth)acrylic acid copolymers; carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, #powdered glycolic acid Examples include modified polymers such as sodium, sodium starch phosphate, and sodium caseinate; natural polymers such as guar gum, xanthan gum, and pullulan.

Examples of powdery water-absorbing resins include polyacrylates, polyhydroxyethyl methacrylate, salts of starch-acrylic acid grafts, etc., all of which are partially crosslinked to reduce water solubility.

These are used as water-absorbing agents in sanitary napkins and the like.

Note that the molecular weight of these hydrophilic resins is not particularly limited. The particle size is usually 8 mesh or less.

Mixing the various powdered hydrophilic resins and dust prevention agent described above,
This can be easily carried out using various mixers such as those explained in the section of the dust prevention agent.

The amount of resin for the powdered hydrophilic resin eruption ζ of the dust prevention agent is usually such that the amount of organic compounds in the former is 0 by weight relative to the amount of the latter.
．． 005-0.5%, preferably 0.01-0.1%,
Particularly preferred is 0.015 to 0.05%. If the amount of the dust generation prevention agent is less than the above amount, the dust generation prevention effect will be insufficient. On the other hand, if the amount of the dust prevention agent is increased, the dust prevention effect will increase, but the effect will reach a ceiling at a certain amount.

For this reason, there is no point in adding the dust-preventing agent beyond the above-mentioned range, and the purity of the hydrophilic resin decreases.

〔Example〕

The present invention will be explained below with reference to Examples, Usage Examples, and Comparative Examples. Hereinafter, in 1ζ, 1 part is a part by weight.

Also, EO is ethylene oxide, PO is propylene oxide, PET-PO, EO adduct is PO, EO adduct of pentaerythritol, TMP-PO, EO is PO%EO adduct of trimethylolpropane, PMAT
AC is polymethacryloyloxyethyltrimethylammonium chloride, FAA is polyacrylamide, S
-AANa graft product indicates starch-sodium acrylate graft product.

Examples 1 to 5 While stirring 50 parts of diatomaceous earth (bulk specific gravity OJ 8, sieve particle size 100 mesh or more J: 8%, average particle size 18 μ) with a high-speed stirring mixer, EO adduct of oleic acid (molecule Q 600
) Spray 50 parts with a spray gun. The mixture was further mixed for 15 seconds to obtain a dust generation preventive agent (Example 1) of the present invention. This product had no coarse particles and the whole felt moist, indicating that organic compounds were uniformly distributed on the diatomaceous earth surface. In the same manner, each dish dust prevention agent (Examples 2 to 5) listed in Table 1 was obtained.

Table 1 Usage Examples 1 to 7 Two dishes of powdered water-soluble resin powder (polymethacryloyloxyethyltrimethylammonium chloride).

Solid! Viscosity 5.5; Polyacrylamide, intrinsic viscosity 22.
0) and one type of water-absorbing resin (partially crosslinked polymer of starch sodium acrylate graft product, polyacrylic acid sorter f)
f1=7o%, crosslinking agent trimethylol bronomantria acrylate (731-0.2%) and dust prevention agent in Table-2
A Nauta mixer 1ζ was added in the amount described in , and the mixture was mixed for 20 minutes to obtain a powdery hydrophilic resin with low dust generation.

Table 2 shows the results of evaluating the dust generation properties of this product.

Note that dust generation property was evaluated using the s2 method.

In the first method, the inner diameter is 66 mm and the height is 101 mm.
Inject 50g of sample into one part of a 0mm pipe, and calculate the number of dust (fine particles) generated at this time at a height of 295m inside the pipe.
The number of counts per minute (CPM) was measured using a digital dust meter [Model P2 manufactured by Sakuide Chemical Instruments Co., Ltd.] at a point of
). A small CPM value indicates low dust generation.

The second dust generation evaluation method is to collect 50g of sample in a 250me glass bottle, shake it for 6 minutes with a shaker,
The presence and extent of adhesion of fine powder to the glass wall was visually determined.

The less or no adhesion of fine powder, the lower the dust generation.

There was no difference in the particle size distribution of the powdered hydrophilic resin before and after the addition of the anti-dusting agent, indicating that no coarse particles were formed due to the addition of the anti-dusting agent. In addition, there was no significant difference in the fluidity of the hydrophilic resin powder before and after adding the anti-dusting agent, and there were no problems with the soil.

Table 2 (l) Table 2 (2) Comparative Examples 1 to 8 0.1 part of diatomaceous material used in the examples, E of oleic acid
0.1 part of O adduct, powdered water-soluble resin PMATAC10
Using 0 parts, the dust generation prevention effect was investigated without complying with the present invention.

Comparative Example 1 Diatomaceous earth, the EO adduct of oleic acid in Example 1, and a powdered water-soluble resin were placed in a Nauta mixer and mixed for 20 minutes.

Comparative Example 2 Diatomaceous earth and a powdered water-soluble resin were mixed in advance in a Nauta mixer for 20 minutes, and then an EO adduct of oleic acid was added and mixed for an additional 20 minutes.

Comparative Example 8 The EO adduct of oleic acid and the powdered water-soluble resin were placed in a Nauta mixer in advance and mixed for 20 minutes, then a diatomizer was added and mixed for an additional 20 minutes to obtain a T-type mixture.

These were compared with Use Example 1.Secondly, dust generation was evaluated. The results are shown in Table 3. The dust prevention effect was extremely small, and the resin powders were all partially lumpy, sticky on the surface, and had poor fluidity.

Table 8 [Effects of the Invention] The dust generation prevention agent of the present invention does not require the conventional method, but instead mixes polyols with poly-1-noacrylamide powder and then mixes inorganic fine powder. It has a superior effect on preventing dust from being generated. Further, dust generation can be suppressed with a smaller addition amount than in the conventional technology. From this, once the anti-dusting agent is produced, a very large amount of the low-dusting hydrophilic resin can be obtained. In addition, the productivity/work efficiency is greatly improved compared to the prior art method.

The effect of the dust prevention agent of the present invention is that the surface of the inorganic powder is covered with a uniform layer of an organic compound, and this organic compound layer strengthens the fine powder in the resin during the mixing operation with the powdered hydrophilic resin. It is understood that the mechanism is that it is adsorbed to.

Shinie, L.”

Claims (1)

[Scope of Claims] 1. Inorganic powder (A) and one or more organic compounds selected from oxyalkylene ether compounds (b_1), lower polyhydroxy compounds (b_2) and esterified derivatives thereof (b_3) ( B) A dust generation prevention agent for powdered hydrophilic resins, characterized in that it is formed by pre-mixing with B). 2. The inhibitor according to claim 1, wherein (b_1) is an oxyalkylene ether monool and/or an oxyalkylene ether polyol.