JPH0413780A - Modified inorganic powder and production thereof - Google Patents

Abstract

PURPOSE:To enable hydrophobic surface-treatment of inorganic powder to impart high heat-resistance and obtain the subject powder effective in improving the dispersibility of fillers, etc., in a heat-resistant resin by adsorbing, spraying or mixing a precursor of a metal oxide gel containing an organic phosphonic acid compound to an inorganic powder. CONSTITUTION:The objective powder having a surface coating layer composed of a complex of an organic phosphonic acid compound and a metal oxide gel is produced by adsorbing, spraying or mixing a precursor of a metal oxide gel (preferably aluminum oxide gel) containing an organic phosphonic acid compound(e.g. phenylphosphonic acid or octylphosphonic acid) to an inorganic powder (e.g. silica gel or calcium carbonate).

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a surface-modified inorganic powder and a method for producing the same, and the inorganic powder according to the present invention is particularly useful as a filler for heat-resistant resin. be.

Conventional technology The surfaces of inorganic fillers and glass fibers filled in polymeric materials are treated with general-purpose surfactants and coupling agents such as silane, titanate, and aluminate. By performing these treatments, the affinity and reactivity with resins have been improved.

Surface modification treatment methods for inorganic powder include methods of mixing it with filler in a solvent and then removing only the solvent, spraying a treatment agent onto the filler and drying it, or adding it in a composite process of filler and resin. There are known methods to do this.

Prior art related to the present invention includes Japanese Unexamined Patent Publication No. 57-16
No. 8954 discloses that treating the surface of an inorganic filler with an organic phosphonic acid salt compound is effective in making it hydrophobic. Also, Solid State Ionics (Solid 5tate Ionics)
) Vol. 26, pp. 63-69 (1988), there is a report on the structure and thermal properties of metal salts of phosphonic acid, but there is no information on the use of this as a surface treatment agent for inorganic powders. Not mentioned. Further, although the flame retardant effect of organic phosphate esters on resins is well known, the above-mentioned publication is the only attempt to improve the interfacial properties by immobilizing them on the filler surface.

Problems to be Solved by the Invention In recent years, the development of heat-resistant resins called super engineering plastics has been remarkable, and those that are stable at temperatures of 400''C or higher have been developed.

However, most of the conventionally known surface treatment agents are
Since decomposition occurs between 0°C and around 300°C, there is a strong need for the development of a surface treatment agent with a high decomposition temperature that can be used for these heat-resistant resins, and the present invention is an attempt to solve this problem. .

Means to Solve the Problem In order to obtain high affinity at the interface between a hydrophilic surface such as an inorganic filler and a hydrophobic resin, it is possible and recommended to introduce a treatment agent that exhibits surface activity to the interface. It's here. As a result of an intensive search for a thermally stable compound that possesses these properties, we discovered that metal oxide gel containing organic phosphonic acid is highly valued in terms of thermal stability.
The present invention has now been completed.

The surface modification treatment of organic phosphonic acid on inorganic powder can be performed by depositing and fixing it as an inorganic salt or an organic ammonium salt by the above-mentioned known method.

The present inventors were able to form a highly thermally stable treated layer by immobilizing a mixed metal oxide gel compound and organic phosphonic acid gel on the surface of an inorganic powder as a deposited layer. Ta. In this case, it can be assumed that the metal oxide gel acts as a good thermal conductor, transmitting the heat added to the organic groups to the powder, and easily dissipating it as lattice energy of the powder.

In addition, the organic phosphonic acids used in the present invention are effective to have a relatively hydrophobic alkyl group or aryl group that has a stable carbon-phosphorus bond. The compound has excellent thermal stability. Therefore, by treating the metal oxide gel layer simultaneously, a more thermally stable surface treatment layer can be formed.

Representative organic phosphonic acid compounds suitable for the practice of the present invention include aromatic phosphonic acids such as phenylphosphonic acid, naphthylphosphonic acid, and common aliphatic phosphonic acids such as octylphosphonic acid, decanephosphonic acid, and dodecylphosphonic acid. Acids and aromatic and aliphatic phosphonic acids into which functional groups have been introduced. In this case, ester groups, methylol groups, and the like that are reactive with heat-resistant resins are effective. Moreover, those having a plurality of phosphonic acid groups in one molecule, and polymers and oligomers containing phosphonic acid groups have excellent adsorption properties and are easily gelled, so that they can be effectively used.

As the metal oxide gelling layer in the present invention, oxide gels of aluminum, titanium, zirconium, etc., or composite oxide gels thereof are effective. Particularly when aluminum is used, the effect of improving not only thermal stability but also dispersibility is remarkable.

Next, a specific processing method will be explained. The processing method is
First, there are two main categories: cases in which the treatment is performed before the filler and resin are combined, and cases in which the treatment is performed during the process of combining the filler and resin. In the former case, ■Method to adjust the pH of the solution and make it gel, ■
There are methods of gelling by adding metal salts or metathesis reaction of a substrate. The latter can be achieved by (1) preparing a reaction product of a metal alkoxide or metal halide and a phosphonic acid compound, and adding it at the time of kneading the filler and the polymeric material. In this case, the ratio of the metal-containing gel to the phosphonic acid metal salt can be arbitrarily changed by changing the mixing molar ratio of the phosphonic acid and the metal alkoxide. Furthermore, this method (2) can also be used in the former process.

Next, the thermal stability of phosphonic acid compounds is in contrast to that of phosphoric acid monoesters, which are easily hydrolyzed at high temperatures. The results of thermal decomposition onset temperature obtained by thermal analysis in air are shown in Table 1, and it can be confirmed that the thermal decomposition onset temperature is from 325 to 558°C, and that it has extremely good heat resistance. Ta. In addition, some phosphonic acid gels were observed to release adhering water in a relatively low temperature range of around 100 to 200°C, but the surface hydrophobization ability before and after the release was hardly affected.

Table 1. Thermal decomposition temperatures of various phosphonate metal oxide gels will be explained in detail with reference to Examples below.

Example 1 After dispersing 50 g of silica gel in 1 dm' of water, 2.0 g of phenylphosphonic acid and 1.5 g of aluminum chloride are added and stirred. While continuing to stir, the pH of this suspension was reduced to 0.
．． When the temperature was adjusted from 6.5 to 7.5 with a 5N aqueous sodium hydroxide solution, an aluminum salt of phenylphosphonic acid and an aluminum hydroxide hydrogel were produced and coated with silica gel. After leaving this silica gel for 24 hours,
After filtering, washing with water and drying at a temperature of 125°C, a silica gel surface-treated with alumina gel containing phenylphosphonic acid was obtained.

Figure 1 shows scanning electron micrographs of the surface-treated silica gel, and Figure 2 shows scanning electron micrographs of the untreated silica gel.A comparison of the two shows that the fine particles on the surface of the untreated silica gel are different from those of the untreated silica gel. It can be seen that by doing this, the surface is covered with a phosphonic acid gel treatment layer, forming a smoother surface.

Example 2 Aluminum borate whiskers 5 with an average fiber length of 25 μm
After dispersing 0 g of aluminum zirconium phenylphosphonate in 1 dm3 of water, adding 5.0 g of aluminum phenylphosphonate and dissolving it by heating, the alcohol solution of tetrabutylzirconium was gradually dropped, and aluminum zirconium phenylphosphonate was added to the whisker surface. A gel is formed. The whiskers were filtered, washed, and dried at a temperature of 140°C to obtain surface-modified whiskers.

The results of thermal analysis of the surface-treated whiskers (in air, heating rate 20°C per minute) are shown in Figure 3, and it was found that thermal decomposition started at around 480°C. .

Next, in order to evaluate the surface hydrophobicity of this whisker,
Aluminum borate whiskers 0.0% in benzene 25d.
When the dispersibility of 25 g was evaluated from the sedimentation volume after 24 hours, the results shown in Table 2 were changed, and a remarkable improvement in the dispersibility was observed.

This book shows the analysis value of phenylphosphonic acid group.

The immobilization rate of phenylphosphonic acid was determined by ultraviolet absorption spectrum measurement (263
rv+) and determined by the calibration curve method.

Figure 4 shows the diffuse reflection infrared absorption spectrum of the surface-treated whiskers, and the absorption bands derived from phenylphosphonic acid are 1145.1121.1034, 102
2+ 979 CI-'.

According to scanning electron microscopy, the whisker surface showed an extremely smooth surface, and no precipitates were observed anywhere other than the surface.

Example 3 1 g of tetrabutylzirconium and 11 ml of acetic acid IJI in 20 methanol! After mixing, 1.5 g of octylphosphonic acid is mixed. This was sprayed onto 50 g of silica gel. After being left for 24 hours, it was heated at 150° C. for 1 hour to obtain surface-treated silica gel.

As a result of thermal analysis of the ice crystals, an exothermic peak due to decomposition of organic groups was observed at around 340°C.

Example 4 30 g of calcium carbonate (average particle size 0.54 μm) was dispersed in 300 d of an aqueous aluminum chloride solution (5χ), and a 10-g aqueous solution of β-phenylethenephosphonic acid (1 g) was added to this.
By gradually dropping the solution, calcium carbonate coated with calcium β-phenylethenephosphonate/aluminum gel was obtained.

As a result of thermal analysis, the starting point of thermal decomposition of ice crystals was 385°C, and this surface-treated calcium carbonate exhibited hydrophobicity and floated on the water surface.

Effects of the Invention According to the present invention, it has become possible to perform hydrophobic surface treatment with high heat resistance, and it has become possible to improve the dispersibility of fillers and the like in the heat-resistant resin.

[Brief explanation of the drawing]

Figure 1 is a scanning electron micrograph of silica gel coated with phenylphosphonic acid aluminum gel according to the present invention, Figure 2 is a scanning electron micrograph of untreated silica gel, and Figure 3 is a scanning electron micrograph of aluminum zirconium phenylphosphonate. Thermal analysis (TG-DTA) chart of aluminum borate whiskers treated with , and Figure 4 shows the diffuse reflection infrared absorption spectrum diagram of aluminum borate whiskers whose surface was modified with aluminum phenylphosphonate/zirconium gel. It is. Figure 1 Patent applicant: Shikoku Kasei Kogyo Co., Ltd. Figure 2 Figure 3 α, w + Figure Boo Cm-1 A photograph showing the particle structure of the untreated silica gel described in Boo Cm-1 Figure 3 is the surface-modified whisker in Example 2 Fig. 4 shows a diffuse reflection infrared absorption spectrum diagram as well. Above C Procedural amendment (method) Display of the case Patent application No. 116288, 1990 Name of the invention Modified inorganic powder and the person making amendments to its manufacturing process Relationship with the case: Date of the order for amendment by the patent applicant July 1990 Contents of the amendment The column for the brief explanation of the drawings of the specification to be amended on the 31st day of the month shall be amended as follows. Record

Claims (2)

[Claims] (1) A modified inorganic powder characterized in that a film made of a composite of an organic phosphonic acid compound and a metal oxide gel is formed on the surface. (2) A method for producing a modified inorganic powder, in which a precursor of a metal oxide gel containing an organic phosphonic acid compound is adsorbed, sprayed, or mixed into an inorganic powder.