JPH02113041A - Coated granule, production thereof and amino resin composition containing same - Google Patents

Abstract

PURPOSE:To obtain the title composition highly resistant to heat discoloration by incorporating an amino resin with coated granules improved in affinity and interlaminar debonding resistance which can, in turn, be obtained by coating the surface of talc with an organic matter layer of moderate thickness having adequate mechanical strength. CONSTITUTION:A reaction is carried out in an aqueous medium in the presence of talc between (A) at least one kind of compound selected from aminotriazine compounds (e.g., melamine), urea and phenols and (B) formaldehyde to form a condensate layer on the talc surface, thus obtaining the objective coated granules containing 10-95wt.% of talc. The other objective composition can be obtained by incorporating an amino resin with 5-70wt.% of the above coated granules.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to composite particles useful as fillers for thermoplastic and thermosetting resins (hereinafter referred to as plastics), a method for producing the same, and a resin containing the same. The present invention relates to a composition.

[Conventional technology]

Fine powder talc is an inorganic filler that is used in large quantities as a filler for plastics and paper manufacturing. When plastics are filled with inorganic fillers, the elastic modulus and heat distortion temperature generally improve, but the tensile strength and impact strength often decrease. This is thought to be due to insufficient affinity between the plastic and the inorganic filler. For this reason, various methods have been studied to improve the affinity of the surface of the inorganic filler for plastics. For example, silane,
Methods using various coupling agents such as titanium-based or chromium-based, oils and fats, higher fatty acids, higher alcohols, etc.
A method using a surface treatment agent such as a plasticizer or a high boiling point hydrocarbon is known.

However, coupling agents and surface treatment agents often do not have a large effect on talc, and depending on the type of plastic, it may be difficult to fill a large amount of talc without damaging the mechanical properties. Are known.

The reason for this is that the above-mentioned known methods are not only insufficient in improving the affinity with plastics, but also that the crystal structure of talc is layered, which tends to cause delamination between the layers. This is said to be due to the fact that the physical properties of the composite plastic are not sufficiently improved just by doing so.

On the other hand, amino resin molding materials have superior properties not found in other plastics, such as arc resistance, tracking resistance, electrical insulation, flame resistance, coloring properties, surface hardness, solvent resistance, and mechanical strength. However, there was a problem with thermochromic properties, which limited its use. It is known that discoloration due to heat is mainly caused by commonly used cellulose fillers, and in order to solve this problem, it is desirable to use inorganic fillers.

Glass fiber, asbestos, etc. have been used as inorganic fillers for a long time. As examples of the use of other inorganic fillers, for example, Japanese Patent Application Laid-Open No. 57-67650 discloses a melamine resin molding material composition co-filled with β-type calcium metasilicate and talc; discloses an amino resin molding composition co-filled with aluminum hydroxide and talc.

However, conventionally known inorganic fillers have the following problems, and improvements have been desired.

For example, in the case of fibrous fillers such as glass fiber and asbestos, disadvantages such as increased warping of molded products due to the orientation of m-fibers are unavoidable, and asbestos is suspected of being carcinogenic. There are problems such as. On the other hand, inorganic fillers with relatively small aspect ratios, such as talc, β-type calcium metasilicate, calcium carbonate, or aluminum hydroxide, have drawbacks such as insufficient mechanical strength.

[Problem to be solved by the invention]

Therefore, the first object of the present invention is to provide composite particles useful as a filler for plastic-based composite materials, in which the surface of talc is coated with an organic layer of appropriate thickness and having sufficient mechanical strength, and a method for producing the same. The goal is to provide the following.

The second object of the present invention is to have excellent heat discoloration resistance, and at the same time,
An object of the present invention is to provide an amino resin composition having mechanical strength comparable to that obtained when a cellulose filler is used.

[Means to solve the problem]

In order to solve these problems, the present inventors discovered that if the surface of talc is coated with an organic layer of appropriate thickness having sufficient mechanical strength, the affinity and delamination properties of talc crystals will be improved. As a result, we conducted extensive research with the idea that the physical properties of plastic composite materials filled with such composite particles would improve. As a result, formaldehyde is reacted with at least one member selected from the group consisting of aminotriazine compounds, urea, and phenols in the presence of talc in an aqueous medium, and a thermosetting resin is coated on the talc surface. The present inventors have discovered that composite particles formed by forming a condensate layer can achieve the above object, and have completed the present invention.

That is, the present invention consists of talc coated with a layer of a condensate of formaldehyde and at least one selected from the group consisting of aminotriazine compounds, urea, and phenols, and the surface of the talc and the condensate layer are The present invention provides composite particles characterized in that they are chemically bonded.

Such composite particles are produced, for example, by reacting formaldehyde with at least one member selected from the group consisting of amino)IJ azine compounds, urea, and phenols in the presence of talc in an aqueous medium, and then forming the particles on the surface of talc. It is manufactured by forming a condensate layer.

The present invention will be further explained in detail below.

The talc used in the present invention is an ore called talc (chemically known as hydrated magnesium silicate 3 M g 0 4 Si 0 2 H
It is a white to gray inorganic powder obtained by finely pulverizing 2O), and it is preferably 300 mesh or less, which is usually available in the market by hand.

The aminotriazine compounds used in the present invention include melamine and guanamines such as benzoguanamine and acetoguanamine.

Further, a part of urea can be replaced with thiourea. As phenols, phenol,
Talezonopexylenol, tert-butylphenonopephenylphenol, naphthol, usually has 2 carbon atoms
Monohydric phenols such as alkylphenols having ~12 alkyl groups, cyclohexylphenonopehalogen-substituted phenols, and resorcinol, bisphenol A1 bishydroxyphenylmethane, bishydroxyphenylethenope bisphenol B1 bisphenol S, etc. Examples include dihydric phenol. In addition to formaldehyde itself, formaldehyde includes formalin, trioxane, rose formaldehyde, etc.
Those that generate formaldehyde can also be used.

In the present invention, the particle surface may be coated with a co-condensation resin using two or more selected from aminotriazine compounds, urea, and phenols. For example, urea-
Melamine cocondensation resins, melamine-phenol cocondensation resins, and the like are also suitable for the condensate layer.

The condensate layer referred to in the present invention comprises at least one compound selected from the group consisting of formaldehyde, aminotriazine compounds, urea, and phenols (hereinafter referred to as amine,
It is formed by a condensation reaction with phenols (called phenols). The degree of condensation of the condensate layer is 3-3- in terms generally used to indicate the degree of condensation of thermosetting resins.
It may be either 5ta or C-C-5ta.

The thickness of the condensate layer can be arbitrarily set depending on the intended use of the composite particles. The degree of condensation of the condensate layer can be increased by a known method in the process of manufacturing the composite particles of the present invention, or in the step of mixing it with plastic or rubber to form a composite plastic or rubber. The mechanical strength of the organic layer reaches the level of ordinary thermosetting resins, providing an organic layer with sufficient mechanical strength.

Next, the chemical bond between the talc surface and the condensate layer will be explained. Talc and other silicate compounds are generally known to have hydroxyl groups on their surfaces. As described below, when formaldehyde and amines/phenols are reacted in the presence of talc in an aqueous medium, the hydroxyl groups on the surface of talc and formaldehyde react to generate active sites such as methylol groups on the talc surface. It is estimated that a water-insoluble condensate layer is formed on the talc surface from this point. In other words, the talc surface and the condensate layer are chemically bonded. The existence of such chemical bonds is evidenced by the following two facts. That is, as shown in Example 1, if appropriate reaction conditions are selected, substantially all of the condensate is water-insoluble at the end of the reaction, and it is easy to observe with a scanning electron microscope. According to the results, only composite particles of the present invention were produced, and particles consisting only of a thermosetting resin not containing talc were not observed. This indicates that substantially all of the condensate was used to coat the talc surface. It is known to those skilled in the art that the condensation reaction mainly proceeds in the aqueous phase, at least in the initial stage of the reaction. The fact that substantially all of the condensate is attached to the talc at the end of the reaction can only be explained by the presence of the above-mentioned chemical bond with the talc surface. In other words, functional groups such as methylol groups (or methylol ether groups) generated on the talc surface become active sites for the reaction, and the initial condensates and amines/phenols generated in the aqueous phase react with these, creating new active sites. is generated. This reacts with the initial condensate in the aqueous phase to generate new active sites. It is thought that by repeating such reactions, a layer of condensate on the talc gradually grows, and eventually the condensate in the aqueous phase becomes substantially absent.

Furthermore, if the reaction conditions are not appropriate, such as when talc and water are added to the initial condensation solution of formaldehyde and melamine and heated and stirred for several hours, the amount of condensate layer formed will be greatly reduced. This is evidence that the condensate layer is not formed by mere physical adsorption onto the talc surface.

In the composite particles of the present invention, the condensate layer and the talc surface are firmly adhered to each other by the above-mentioned chemical bond, so it is possible to use a method that is merely physical and can substantially ignore the presence of chemical bond with the talc surface, for example. A method of simply physically mixing and drying an initial condensation liquid of a thermosetting resin prepared by a conventional method and talc,
Alternatively, they are essentially different from composite particles produced by coating the surface of talc with a thermosetting resin heated and melted.

The talc content in the composite particles of the present invention is 10 to 95% by weight.
is preferred. If it is less than 10% by weight, it is difficult to control the particle size, and if it exceeds 95% by weight, problems such as a decrease in performance as a filler tend to occur.

The composite particles of the present invention obtained as described above can also be made into enlarged composite particles by secondary aggregation of the composite particles covered with the condensate layer by selecting reaction conditions. The degree of such secondary aggregation can be controlled by changing the reaction conditions, as will be described later. The particle size of the composite particles can be set in a wide range up to enlarged composite particles consisting of physical aggregates.

Next, a method for producing composite particles of the present invention will be explained.

First, the method of the present invention involves reacting formaldehyde with amines/phenols in an aqueous medium in the presence of talc.

Although the order of addition of each component is not particularly limited, usually the required amount of talc is first suspended in water, then formaldehyde is added, and finally amines and phenols are added. Since there is a tendency for the yield of solid content to be increased when formaldehyde is added first, it is usually desirable to follow the above order of addition. There are no particular restrictions on the timing of temperature rise, but usually the temperature is raised after formaldehyde is added, and the amine is added after the temperature approaches the predetermined reaction temperature, or after a certain period of time after the predetermined reaction temperature is reached. It is desirable to add phenols.

Here, the solid content is the sum of talc and the condensate layer covering the surface of the talc, and the condensate layer is insoluble in water at the time of completion of the above reaction.

When the talc used is treated with an acid before the reaction begins, the yield of solids tends to increase compared to when it is not treated.

The acid treatment may be carried out by contacting the talc with an acid in advance outside the reaction system, or by suspending talc in water within the reaction system and then adding an acid within the range where the pH of the system does not fall below 2. May be added. The type of acid used is not particularly limited, but includes, for example, inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and phosphoric acid, carboxylic acids such as formic acid, cicholic acid, acetic acid, tartaric acid, citric acid, and maleic acid, and p-) Sulfonic acids such as luenesulfonic acid and alkylbenzenesulfonic acid having an alkyl group having 10 to 18 carbon atoms can be used.

In the present invention, a basic catalyst can be used in the above reaction.

As the basic catalyst, catalysts used in the production of ordinary melamine resins, urea resins, or resol-type phenolic resins can be used, such as aqueous ammonia, pyridine, hexamethylenetetramine, dimethylamine, diethyltriamine, polyethyleneimine, etc. alkylamines, and inorganic bases and inorganic salts such as hydric soda, hydric potassium, sodium carbonate, potassium carbonate, and calcium hydroxide can be used.

The reaction of the present invention is carried out in an aqueous medium, and in this case, the amount of water charged is such that the solid content concentration at the end of the reaction is 10 to 8.
It is desirable that the content be 0 wt%, preferably 30 to 70 wt%. The reaction of the present invention is carried out under stirring or kneading, at a reaction temperature of 40 to 100°C, and a reaction time of 1 to 10°C.
Time is preferable.

In the method of the present invention, the degree of secondary aggregation of the condensate layer is determined by the ratio of talc and the amount of amine/phenol added, the type of amine/phenol, reaction temperature, reaction time, kneading or stirring speed, and surface activity. It can be controlled by reaction conditions such as the type and concentration of the agent or the concentration of water-insoluble solids.

The molar ratio of formaldehyde and amines/phenols is
Desirably, the range is within the range employed in common melamine resins, urea resins, phenol resins, urea-melamine cocondensation resins, melamine-phenol cocondensation resins, etc., and 1 to 3 is usually preferred.

Also, regarding the degree of condensation or degree of curing of the condensate layer,
At least at the end of the reaction, it must become insoluble in water due to chemical bonding with the talc surface or crosslinking reaction between condensates.

Furthermore, the crosslinking reaction of the condensate can be promoted by adding an acid when the reaction has progressed to a certain extent. The acids that can be used here are the same as those used in the acid treatment of talc described above.

In the method of the present invention, a surfactant can be used as described above in order to control the degree of secondary aggregation of composite particles. The type of surfactant that can be used is not particularly limited, and various commercially available surfactants (anionic, cationic, and nonionic) can be used alone or in combination.

After the reaction is completed, the reaction system is cooled to 50°C or less, and solid-liquid is separated by a conventional method such as filtration or centrifugation, and then washed with water.
After drying, the composite particles of the present invention can be obtained. During drying, the degree of condensation can be controlled to some extent by selecting the temperature and time.

The composite particles obtained by the method of the present invention as described above are coated with an organic material layer of an appropriate thickness having sufficient mechanical strength, and any particle size can be set within a wide range. can.

The present invention also provides an amine resin composition containing the above composite particles.

The amino) sealants used in the present invention include melamine resins, urea resins, guanamine resins, and their modified products such as phenol/melamine resins, guanamine/melamine resins,
Phenol/urea resin, urea/melamine resin, phenol/guanamine resin, urea/guanamine resin, etc. are suitable. Here, as the guanamine, at least one selected from benzoguanamine and acetoguanamine can be used. Further, as the phenol, at least one selected from the above-mentioned phenols can be used.

The content of the composite particles is preferably 5 to 70% by weight based on the total amount of the amino resin composition. If it is less than 5% by weight, the effect of containing it cannot be obtained sufficiently, and if it is less than 70% by weight.
Exceeding this tends to cause problems such as poor moldability.

The method for obtaining the amino resin composition of the present invention from the above-mentioned amine resin and composite particles is not particularly limited, and various commonly used methods can be used. For example, a method of mixing an initial condensation liquid of an amino resin and the composite particles and drying the mixture, or
The method includes pulverizing, mixing, or kneading the solid amine resin and the composite particles using a commonly used means such as a ball mill, roll mill, or kneader. The amine resin composition of the present invention may contain commonly used curing agents, mold release agents, coloring agents, and the like. If desired, the composite particles may be co-filled with at least one filler selected from cellulose fillers such as bulbs and wood flour, and inorganic fillers such as calcium carbonate and aluminum hydroxide.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 1200 g of water was placed in a 41 separable flask equipped with a condenser, and while stirring, 350 g of talc with an average particle size of 2.3 μm was added to obtain a talc suspension. When 2.5 g of 19 wt % hydrochloric acid was added to this and stirred at room temperature for 30 minutes, the pH was 6.8 (BTB). The reason why there is almost no decrease in pH is that some of the talc is eluted and neutralizes the acid. Next, after adding 300 g of formalin, the temperature was started to rise to 90° C. in 40 minutes and maintained at the same temperature for 20 minutes. Furthermore, 240 g of melamine was added and reacted at 90° C. for 5 hours with strong stirring.

The flask contents were then cooled to 50° C. and washed with 21 portions of water while being filtered. The obtained solid content was dried in a hot air dryer at 80° C. until it reached a constant weight.

The yield of solid content was 638 g. In this way, composite particles of the present invention, which are talc coated with a layer of formaldehyde and melamine condensate, were obtained. When this composite particle is observed under an electron microscope, it is found that the average particle size is approximately 20 μm, that secondary aggregation has occurred, and that there are no particles consisting only of the thermosetting resin.

Example 2 1000 g of water was placed in a 41 separable flask equipped with a condenser, and while stirring, 300 g of talc having an average particle size of 2.3 μm was added to form a talc suspension. To this was added 2.5 g of 19 wt % hydrochloric acid, and the mixture was stirred at room temperature for 30 minutes. Then 37
After adding 360 g of wt% formalin, the temperature was raised to 60°C,
It was kept at the same temperature for 40 minutes. Next, add 180g of urea,
Further, 80 g of 19 wt % hydrochloric acid was slowly added in small portions several times, and the reaction was allowed to proceed at the same temperature for 5 hours. Thereafter, sodium carbonate was added to adjust the pH of the reaction solution to 7.

The contents of the flask were then cooled to 50°C, filtered and
Washed with β water. The obtained solid content was dried in a hot air dryer at 80°C until it reached a constant weight. The yield of solids is 50
It was 3g. Thereby, composite particles of the present invention, which were talc coated with a layer of a condensate of formaldehyde and urea, were obtained. The average particle size was approximately 3 μm and no secondary agglomeration was observed.

Example 3 400 g of water was placed in a 41 separable flask equipped with a condenser, and 400 g of talc having an average particle size of 2.3 μm was added while stirring. After adding 100g of 37wt% formalin to this, the temperature was raised, and when it reached 85℃, phenol 1'00
g and 4 g of anhydrous sodium carbonate were added. After reacting at the same temperature for 3 hours, 100 g of 10% hydrochloric acid was slowly added little by little over time, and the reaction was continued for an additional 2 hours.

Next, add sodium carbonate to neutralize, and adjust the pH of the reaction solution.
was set as 7.

After cooling to 50° C., the mixture was washed with 21 portions of water while being filtered.

The obtained solid content was dried in a hot air dryer at 80° C. until it reached a constant weight. The yield of solid content was 490 g. Thereby, composite particles of the present invention, which were talc coated with a layer of a condensate of formaldehyde and phenol, were obtained. The average particle size was approximately 50 μm.

Example 4 After adding 1000 g of water, 300 g of talc with an average particle size of 2.3 μ, and 165 g of 37 cit% formalin to a separable flask with a condenser (No. 41), the temperature was started to rise, and after reaching 85°C, 38 g of phenol was added. and anhydrous sodium carbonate 1.5
g was added. After reacting at the same temperature for 1 hour, melamine 1
13 g and 75 g of 1Qwt% hydrochloric acid were added, and the reaction was continued for an additional 5 hours. Thereafter, sodium carbonate was added to neutralize the mixture to a pH of 7. This was cooled to 50°C, filtered and washed with 2β water. The obtained solid content was dried in a hot air dryer at 80° C. until it reached a constant weight. The solid content yield is 43
It was 5g. Thereby, composite particles of the present invention, which were talc coated with a layer of a co-condensate of formaldehyde, melamine, and phenol, were obtained. The average particle size is approximately 3
It was 0 μm.

Example 5 1000 g of water 1 300 g of talc with an average particle size of 12 μm was added to a 41 separable flask equipped with a condenser to prepare a talc suspension. Add 2.5 g of 19 wt% hydrochloric acid to this and
Stirred for 0 minutes. Then, 37 wt% formalin 360
After adding g, the temperature was raised to 87°C and maintained at the same temperature for 40 minutes. Next, 180 g of melamine and 2.6 g of sodium hydroxide were added, and the mixture was reacted for 1 hour at the same temperature with strong stirring. moreover,
Add 120g of urea and 70g of 10% hydrochloric acid and heat at 60℃ for 5 minutes.
Allowed time to react. The flask contents were then cooled to 50°C, filtered and washed with 2β water. The obtained solid content was dried in a hot air dryer at 80° C. until it reached a constant weight. The yield of solid content was 637 g. Thereby, composite particles of the present invention, which were talc coated with a layer of a co-condensate of formaldehyde, melamine and urea, were obtained. The average particle size was approximately 15 μm, and no secondary aggregation was observed.

Example 6 1200 g of water was placed in a 41 separable flask equipped with a condenser, and while stirring, 350 g of talc having an average particle size of 2.3 μm was added to obtain a talc suspension. Next, formalin 300
After adding 240 g of melamine and 240 g of melamine, the temperature was increased to 90° C. in 40 minutes, and the reaction was continued at the same temperature for 5 hours with strong stirring. In addition, 40 minutes after reaching 90°C, a nonionic surfactant (manufactured by NOF Corporation, Nonion NN5) was added.
-210)3 was added.

Also, 4 hours after reaching 90°C, 0. IN phosphoric acid was added using a plunge bomb at a rate of ld/min for 30 min.

The contents of the flask were then cooled to 50°C, filtered and
Washed with water from A. The obtained solid content was dried in a hot air dryer at 80° C. until it reached a constant weight.

The yield of solid content was 642 g. As a result, Example 7
Composite particles used in the above were obtained. No secondary aggregation was observed in the composite particles, and the average particle size was approximately 4 μm.

Example 7 1800 g of 37% formalin, 510 g of water, and 10 wt of sodium hydroxide in a 41 separable flask with a condenser.
% aqueous solution and 1590 g of melamine were charged and reacted at 90° C. for 60 minutes to obtain an initial condensation liquid of melamine resin.

One-third of the above-mentioned initial condensation liquid and 634 g of the composite particles obtained in Example 6 were kneaded in a Ni-Goo and dehydrated under reduced pressure. The solid content thus obtained was dried in a hot air oven at 80° C. for 2 hours to obtain the amine resin composition of the present invention. The talc content in the composition is 27.5 wt%.

0.4 parts of zinc stearate per 100 parts of the above composition;
0.1 part of phthalic anhydride was added and pulverized in a ball mill to obtain a powdered molding material.

Comparative Example 1 A bulb-filled powder molding material was obtained in the same manner as in Example 7, except that 270 g of bulb was added to one-third of the initial condensation liquid obtained in Example 7 instead of the composite particles.

Comparative Example 2 A talc content of 2.7 μm was prepared in the same manner as in Example 7, except that 241 g of talc with an average particle size of 2.3 μm was added to one-third of the initial condensation liquid obtained in Example 7 instead of the composite particles. A powdered molding material filled with .5 wt% talc was obtained.

Table 1 shows the mechanical properties of the molding materials of Example 7 and Comparative Examples 1 and 2.

Table 1 Next, the heat discoloration resistance of the molded products of Example 7 and Comparative Example 1 was measured. Table 2 shows the relationship between the degree of discoloration (ΔE) and the processing time.

The measurement conditions were as follows.

Processing temperature = 170°C Processing atmosphere: Air Colorimetric color meter: Nippon Denshoku Kogyo, double beam cross-illumination method % formula % From the results in the table above, the molded product of Example 7 has a high mechanical strength. It can be seen that the results are equivalent to or better than those using cellulose-based fillers, and at the same time, they have excellent heat discoloration resistance.

〔Effect of the invention〕

The composite particles of the present invention have particle surfaces coated with a layer of condensate of formaldehyde and amine/phenols,
Since the condensate layer is chemically bonded to the talc surface,
It has a true specific gravity lower than that of talc, has good compatibility with organic substances, high mechanical strength, high heat resistance and heat discoloration resistance, and is excellent in flame retardancy. Taking advantage of these features, it can be advantageously used as a reinforcing agent and filler for various plastics and rubbers.

If desired, enlarged composite particles can be obtained by secondary agglomeration of talc coated with a condensate layer.

Further, according to the production method of the present invention, the composite particles described above can be produced extremely easily and stably.

Furthermore, the amine resin composition of the present invention has excellent heat discoloration resistance, mechanical strength equal to or greater than that using cellulose fillers, and at the same time, molded products have less warpage. have. Taking advantage of these features, it is used as heat-resistant electromechanical parts and heat-resistant tableware.

Claims (5)

[Claims] (1) Consists of talc coated with a condensate layer of formaldehyde and at least one selected from the group consisting of aminotriazine compounds, urea, and phenols, and the surface of the talc and the condensate layer are chemically Composite particles characterized by being bonded together. (2) The content of talc in the composite particles is 10 to 95% by weight
The composite particle according to claim (1). (3) In the presence of talc in an aqueous medium, at least one member selected from the group consisting of aminotriazine compounds, urea, and phenols is reacted with formaldehyde to form a condensate layer on the talc surface. The method for producing composite particles according to claim (1), characterized in that: (4) An amino resin composition containing the composite particles according to claim (1) or (2). (5) The composite particles are 5 to 5% of the total amount of the amino resin composition.
The amino resin composition according to claim 4, containing 70% by weight.