JPS637911A - Granular melamine resin molding material - Google Patents

Abstract

PURPOSE:To obtain a granular melamine resin molding material showing excellent suitability in prevention of dusting, degradation resistance and shock resistance of a molded product, by specifying grain distribution, mean hardness and hardness dispersion. CONSTITUTION:The title material is a granular melamine resin molding material composed of a hot extrusion molded material of powder of a composition for melamine resin molding by recrushing the same. Grain distribution of the material satisfies a thing of less than 3wt% which does not pass through a 24 mesh screen, a 25-60wt% thing which passes through the 24 mesh screen and does not pass through a 42 mesh screen, a 25-60wt% thing which passes through the 42 mesh screen and does not pass through a 145 mesh screen and a thing of 10wt% or more and less than 24wt% which passes through a 145 mesh screen. When hardness X(kg/cm<2>) is displayed with (1-alpha)x<=x<=(1+alpha)x {provided that x is mean hardness (kg/cm<2>) and alpha is an index number showing a dispersion range of the hardness}, x and alpha are decided so as to fall within a range of 80<=x<=300 and 0.3<=alpha<=0.7. In addition, it is preferable that an angle of repose is 40 deg. or more and less than 50 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention provides 1 granule type granules having excellent improved properties, which are obtained by re-crushing a heated extrusion molded product of melamine resin molding composition powder. Regarding melamine resin molding materials,
In addition to excellent self-needling properties (powder flow properties) and prevention of tortoiseshell spots, it also has particularly excellent dust prevention properties, disintegration resistance, and
This invention relates to a granular melamine resin molding material that exhibits suitability for preheating tableting (preforming tabletting), cold compression pellet strength, molded product crack resistance, and molded product impact resistance.

More specifically, the present invention provides granular melamine at
The present invention relates to a granular melamine resin molding material which is a finger molding material and is characterized by having a specific particle size distribution, and having a specific average hardness and specific hardness variations.

[Conventional technology]

Conventionally, mixed wire containing melamine Wt + umami liquid and pulp,
A powder composition for melamine resin molding obtained by crushing a dry composition so-called "pop corn", and furthermore, such a powder composition for melamine resin molding is once pelletized (or tableted) and then crushed again. It has been widely known to prepare molding granular compositions of coarse and fine granular molding particles, so-called "granules".

In the former type of powder composition for molding, the fine powder that passes through a 200-mesh sieve usually accounts for 70% by weight or more, and has the advantage that the resulting hot-press molded product has fewer problems such as tortoiseshell spots. However, on the other hand, there are problems such as defects in powder (dust generation), and insufficient powder flowability that makes it unsuitable for automatic metering. On the other hand, the latter type of powder composition for molding of the "Granille" type exhibits satisfactory dust prevention properties and powder flowability, but on the other hand, there is a problem of tortoiseshell spots occurring in the resulting hot-press molded products. .

Furthermore, according to the studies of the present inventors, in the former type of molding powder composition, prior to hot-pressing the composition, the composition is preheated and filled, for example, by high-frequency preheating. When making tablets, molding powder adheres to the inner wall of the preheating frame, requiring complicated and time-consuming cleaning of the frame, and if this is neglected, often
It has been found that there is a problem in which highly hardened pieces get mixed into the molded product and reduce the value of the molded product. On the other hand, with the latter 1 granule type molding powder composition, the above-mentioned troubles do not occur, but even if it is attempted to form a preheated tablet, it is difficult to obtain a tablet due to handling precautions, and the shape collapses. There is a drawback that it is not possible to form a practical preheated tablet.Therefore, a method is adopted in which the material is directly supplied to the molding machine and hot-pressed without being preheated, and the disadvantage of extending the molding cycle cannot be avoided. , There is also a problem that promotes the occurrence of tortoiseshell spots.

Heretofore, several proposals have been known to overcome the trouble of occurrence of tortoiseshell spots.

For example, in JP-A-51-79143, the hardness of the amino resin granular molding material is x (lcp/+l), the particle size is t
As y(■), an amino acid characterized by having a ratio of 80% or more within the area surrounded by the triangular curve represented by the following formula % ([]) A resin granular molding material composition has been proposed and is disclosed to be useful for preventing the occurrence of tortoiseshell spots.When the above particle size conditions are expressed in terms of mesh, the powder that does not pass through a 145 mesh sieve has a coefficient of 80 or higher, that is, The amount of powder that passes through the No. 145 mesh sieve is 20% or less, but there is no description or disclosure regarding the specific particle size distribution or specific hardness variation in the present invention, and in this proposal, the suitability for preheating tableting, the cooling There is no mention of intercompression tablet strength, molded product crack resistance, or molded product impact resistance.

In addition, as another proposal, JP-A-57-468 (No. 13) includes the following particle size distribution: 20-42 mesh particle size product, 0-20 weight coefficient -4
2 to 145 mesh 50 to 90 weight/f% 145 mesh passing particle size product An amine resin molding material with an essential requirement of 0 to 50 weight/t% has been proposed, and has excellent properties in preventing the occurrence of tortoiseshell spots and automatic weighing performance. It is stated that As yet another proposal which has the same purpose as the above proposal and may overlap with the above proposal, Japanese Patent Application Laid-Open No. 57-46804 proposes an amine resin molding material composed only of powder that passes through a 20-mesh sieve but does not pass through a 145-mesh screen. Are known.

These proposals do not disclose at all about a resin molding material consisting of a re-shredded product of a heated extrusion molded composition powder, and which has a specific average hardness and specific hardness variations, and also does not disclose the particle size. In addition, there is no mention of the material's disintegration resistance, suitability for preheating tableting, cold compression tablet strength, molded product crack resistance, and molded product impact resistance.

The present inventors previously conducted research for the purpose of solving the incompatible difficulties or troubles in the above-mentioned two types of melamine PM resin molding materials.
Particle size distribution below as 0 weight ratio (a) Powder that passes through a 24 mesh sieve and does not pass through a 42 mesh sieve, (b) Powder that passes through a 42 mesh sieve and does not pass through a 145 mesh sieve, weight ratio of 17 to 47 (c) Powder passing through a 145-mesh sieve weighs 25 to 65 weight 1
% and is a re-shredded product of a heated extruded molding raw material powder containing pulp and melamine resin, which has excellent automatic metering suitability and low helicitis occurrence. They discovered and proposed a powder composition for melamine resin molding that exhibits particularly excellent suitability for preheating tableting, cold compression tablet strength, and crack resistance in molded products, as well as preventive properties (Japanese Patent Application Laid-Open No. 59-8749). ).

As a result of further research, we found that the particle size distribution differs from that proposed by the earlier application, especially in the area where there are very few particles that pass 145 mesh, but the particle size distribution of particles that do not pass 145 mesh,
In addition, by selecting the average hardness and hardness variation width of the granular molding material, we can improve the proposed properties, such as excellent automatic weighing suitability, hexagonal inflammation prevention property, preheating tableting suitability, cold compression tablet strength, and molded product crack resistance. The present invention was completed by discovering that a granular melamine resin molding material possesses all of the excellent properties and exhibits excellent powder dust prevention properties, disintegration resistance, and molded product impact resistance.

[Structure of the invention]

That is, the present invention provides a granular melamine resin molding material obtained by re-fragmenting a heated extrusion molded product of melamine I1M resin molding composition powder, and A. The particle size distribution is such that the total amount of the molding material is 100% by weight. (A) Items that do not pass through a 24-mesh sieve, less than 3 ft'fb, (B) Items that pass through a 24-mesh sieve and do not pass through a 42-mesh sieve, 25 to 60 weight (L-Category), (C) 42-mesh sieve. Those that pass through a sieve but do not pass through a 145 mesh sieve satisfy the following criteria: Average hardness (kg/etl), α
is an index representing the range of variation in hardness), where Ma (kg/d) and α are in the range of a, 80≦i≦300 b, 0.3≦α≦0.7. The present invention provides a melamine resin molding material.

The above objects and many other objects and advantages of the present invention will become more apparent from the following description.

As the melamine resin molding composition powder used for preparing the granular melamine resin molding material of the present invention, preferably, a powder obtained by processing so-called popcorn into a powder having a particle size suitable for hot extrusion molding can be used.

Examples of such a melamine molding composition powder include, for example, a 36% formalin aqueous solution and/or a melamine crystal powder, which can be produced by a known method such as a carbide method or a urea method, per mole of melamine crystal powder. or in the form of paraformaldehyde, about 1% formaldehyde
Melamine I, A fat liquid obtained by reacting in an aqueous medium at a reaction molar ratio of about 2 moles at a pH of about 7 to about 9, for example, a resin solid concentration of about 40 to about 60 weight ft'! Pulp (alpha-cellulose) in melamine ttuh liquid, the resulting composition powder weight based on you, for example about 20 ~
If desired, other additives may be added, kneaded, and dried at a temperature of, for example, about 70 to about 100°C, so that the diameter is, for example, about 3 cr to about 0.
．． One example is a pulverized popcorn product obtained by pulverizing so-called popcorn of about 5 cm.

The above-mentioned pulverization treatment can be carried out using, for example, an impact hammer mill, a ball mill, a vibration mill, or a tower mill. If desired, the powder may be pre-pulverized using, for example, an impact hammer mill, and then further processed to a fine powder using a ball mill, a vibration mill, a tower mill, or the like. Commercially available valve and melamine resin-containing molding powders can also be used, and if desired, commercially available molding powders can be further pulverized and used.

When producing the above-mentioned melamine resin liquid, a part of melamine can be replaced with another thermosetting resin-forming component that can be cocondensed. Examples of such ingredients include guanamines such as benzoguanamine, acetoguanamine, and CTU guanoamine, ureas such as thiourea and urea, phenols such as phenol, xylenol, cresol, and bisphenol A, epoxy compounds, and polyesters. Examples include compounds. It is best to use such components in an amount that does not substantially reduce the desirable water resistance, chemical resistance, solvent resistance, arc resistance, etc. of the melamine resin (e.g., an equivalent amount (by weight) of the melamine resin). ) Hereinafter, the amount to be used may preferably be 40 parts by weight or less based on the total weight of melamine and the above-mentioned thermosetting resin-forming component.

A kneader, co-kneader, etc. can be used as a kneading means for forming the popcorn, and as a drying means,
Examples include hot air drying, band dryer drying, and fluidized drying.

In addition, other additives mentioned above include, for example, titanium oxide,
Zinc oxide, zinc sulfide, red iron, dark blue, barium sulfate,
Iron black, ultramarine blue, carbon black, lidhon, titanium yellow, cobalt flu, Hansa yellow, benzidine yellow, lake red, aniline black, dioxazine violet, quinacridone red, quinacridone violet, naphthol yellow, phthalocyanine blue, phthalocyanine green, etc. Inorganic or organic pigments: zinc stearate, zinc myristate, aluminum stearate, calcium stearate, butyl stearate, stearyl stearate, dioctyl phthalate, diptyl phthalate, stearamide, e-caprolactam, oleic acid amide, linoleic acid Lubricants such as amide, polyethylene glycol, stearyl alcohol, polyoxyethylene stearate, glycerin, polyethylene glycol monooleate, etc.: phthalic anhydride FF, p-1 luenesulfonic acid, dimethyl oxalate, dibenzyl oxalate, dimethyl phthalate, Benzoyl peroxide, epichlorohydrin, p-toluenesulfonic acid triethanolamine salt, 2-aminoethylsulfonate/acid, dimethyl hydrochloride, aniline sulfonic acid, melamine oxalate, ammonium chloride, ammonium phosphate, trimethyl phosphate, acetamide, Examples include curing catalysts such as oxamides.

In the present invention, the above particle size distribution requirements (a), (b), (c) and (i) are met by re-crushing a molded product obtained by hot extrusion molding of the melamine resin molding composition powder as described above. To obtain a satisfactory granular melamine resin molding material.

The above-mentioned hot extrusion molding can be performed using an extruder under appropriate temperature conditions. The type of extruder can be selected as appropriate, and examples include a -screw extruder and a twin-screw extruder. The compression ratio and temperature can be selected as appropriate, for example from 1 to
Examples include a compression ratio of 3, and temperature conditions such as about 50 to about 130°C. The extrusion end of the extruder may be of any type, such as an open type or a screen-like die type, and the twin-screw extruder may be of either a twin-screw type in the same direction or a twin-screw type in opposite directions.

Furthermore, the heated extrusion molded product can be roll-pressed prior to pulverization, if desired.

In the present invention, the heated extrusion molded product of the composition powder that can be formed as described above is re-shredded to obtain a re-shredded product that satisfies the above-mentioned particle size conditions.

This re-shredding means that the particle size distribution of the re-shredded material is less than 0% by weight of the material that does not pass through a 24-mesh sieve, based on the total weight of the molding material; Items that pass through the 42 mesh sieve 25~605~
60% by weight Passes through a 42 mesh sieve and does not pass through a 145 mesh sieve 25-60% by weight, 25 to 60% by weight passes through a 145 mesh sieve 100% by weight Above, 2
This can be carried out using any shredding means that can form a re-shredded product with a content of less than 44% by weight. If desired, sieving methods can be used in combination. Examples of crushers used for such crushing include impact crushers, hammer mills, totomizers, hin mills, roll mills, pulpizers, and the like.

Further, the granular melamine resin molding material of the present invention preferably has an angle of repose of 40 or more and less than 50. If the angle of repose is too small (less than 40), problems such as helicitis may easily occur.Furthermore, when making preheated tablets,
There is a tendency for inconveniences such as deterioration of the shape retention of the tablet, and if the above-mentioned angle of repose exceeds 50°, the suitability for automatic weighing tends to deteriorate.
It is preferable that the angle of repose is 40° or more and less than 50°, since this tends to cause defects such as reduced dust prevention suitability and, furthermore, poor preheating tableting suitability.

During the above-described re-crushing treatment for producing the composition of the present invention, other additives may be added, if desired. Examples of such additives include pigments, lubricants, curing catalysts, and the like that are exemplified as additives that may be added during the formation of the raw material powder described above.

Based on the weight of the composition of the present invention, examples include pigments in an amount of about 10% by weight or less, lubricants in an amount of about 5% by weight or less, and curing catalysts in an amount of about 5% by weight or less. .

The granular melamine resin molding material, which is a re-shredded product of the hot extrusion molded product of the melamine resin molding composition powder of the present invention, satisfies the particle size distribution requirements of (a), (b), H, and (b) above. do.

If the amount of the material that does not pass through the 24-mesh sieve in requirement (a) exceeds 3% by weight, the strength of the cold-pressed tablet will be poor, the hexagonal spots will easily occur, and the crack resistance and durability of the molded product will deteriorate. Impact resistance also decreases. If the amount of material that passes through a 24-mesh sieve but does not pass through a 42-mesh sieve in requirement (b) is less than 255% by weight, the suitability for automatic weighing and suitability for preheating tablets may deteriorate, or 60% by weight If the total amount is exceeded, the crack resistance, impact resistance, and cold compressed tablet strength will deteriorate, and tortoiseshell spots will be more likely to occur.

In addition, if the amount of material that passes through a 42 mesh sieve but does not pass through a 145 mesh sieve is less than 255% by weight (requirement (c)), the suitability for automatic weighing, crack resistance, and impact resistance will be unsatisfactory. If the amount exceeds 600% by weight, the suitability for forming a preheated tablet and cold compression tablet strength will deteriorate, and the crack resistance and impact resistance will also be deteriorated.

Furthermore, the number of items passing through a 145 mesh sieve is 10
If the amount is too low (less than T1t%), crack resistance, impact resistance, and cold compression tablet strength will deteriorate, and tortoiseshell spots will be less likely to occur.On the other hand, 25! If the amount exceeds t%, the suitability for automatic measurement, suitability for preheating tablets, and dust prevention properties may deteriorate.

For the reasons stated above, the particle size distribution is (a) less than 2% by weight of particles that do not pass through a 24-mesh sieve;
b) 25-55% by weight of materials that pass through a 24-mesh sieve but do not pass through a 42-mesh sieve; (c) 25-55% by weight of materials that pass through a 42-mesh sieve but do not pass through a 145-mesh sieve; 155% by weight, 2
Quadruple 4#: It is preferable that it satisfies less than the ratio.

Furthermore, the granular melamine of the present invention! ! Hardness x (kq/Cj
) is expressed by the following formula (% formula %) (where, the average hardness of the molding material (ky/cJ), α is an index representing the range of variation in hardness), when Ma (kg/, , +f) and α are a180≦
It is necessary that the ranges are Ma≦300 blo and 3≦α≦0.7.

The above-mentioned hardness X and average hardness x (ky/c-J) are measured by a method similar to the Jupiter method, as described later.

If the value of the above value is less than 80 and becomes too small, the collapse resistance of the fragments may decrease, the suitability for automatic weighing, and the suitability for making preheated tablets may deteriorate, and when it exceeds 300 and becomes too large, This is not preferable since the cold compression tablet strength deteriorates, hexagonal spots are likely to occur during molding, and the crack resistance and impact resistance of the molded product also tend to decrease.

In addition, if the value of α is less than 0.3, which is too small, the cold compression tablet strength will deteriorate and the impact resistance of the molded product will tend to decrease, and if it exceeds 0.7, it will be too small. If this happens, the disintegration of the fragments and the suitability for automatic weighing are likely to deteriorate, which is undesirable.

As mentioned above, in the granular melamine resin molding material of the present invention, which is a refined product of a heated extrusion molded product of melamine mqh molding composition powder, Requirements A (a), (b), (c) and - It is essential to satisfy the particle size distribution condition and the hardness conditions a and b of requirement B, and according to the present invention, for example, automatic weighing suitability is preferably 2.0 or less, more preferably 8 or less. , the suitability for preheating tableting is preferably 15.
cycle or more, preferably 18 cycles or more, cold compression tablet hardness is preferably 40 ume/- or more, preferably 60 kf/i or more, dust prevention aptitude is preferably 10 width or less, preferably 5% or less, the collapse resistance is preferably 5% or less, more preferably 3% or less,
Molded product crack resistance is preferably 3-1 cycles or more,
It is preferably 3-3 cycles or more, especially 4-1 cycles or more, and the molded product has an impact resistance of preferably 60 cM 1
It is possible to provide a melamine resin powder composition that has excellent properties such as 0 times or less, preferably 60 times to 30 times or more, and exhibits excellent improving properties without the risk of causing tortoiseshell spots.

In addition, in the present invention, the mesh conforms to JIS, 6911-1.
979, 31, as follows:

■1 Particle size measurement method (method for mesh sieving) JIS
Approximately 502 samples were collected in accordance with 2-6911-1979, 3, 1, using a rotary tube shaker and JIS.

Sieve for 10 minutes using a 200φ standard sieve under the following conditions: rotor tube rotation speed 290 times/minute, number of blows 156 times/minute, total amplitude 28 mm. Next, the weight i- of the sample remaining on each sieve and the sample on the saucer is measured, and the weight % is calculated.

In addition, the hardness X and average hardness x of the molding material in the present invention
(kg/d 2 ) and an index representing the width of variation (hereinafter sometimes abbreviated as variation index) α are measured as follows.

■Measuring method of zero particle hardness Using a particle hardness meter with an improved mechanism in which the spring scale mechanism of a barber shop type hardness meter is replaced with a compression type load cell mechanism, the voltage change of the load cell corresponding to the pressure change applied to the sample particle is measured electrically. have it recorded. The load value (rostrum) at the yield point peak of the particle hardness or its load (kq) per hour (second) curve is determined by measuring the projected cross-sectional area of the sample particle (automatic area meter Luzetx 210).
(measured using Nippon Regulator)) divided by (
ky/1yA). The sample used was a random sampling of 30 particles that passed through 20 meshes but did not pass through 42 meshes, and the maximum value X max, minimum value X for the remaining 20 particles after removing 5 values above and below the calculated value
Determine m1n-, and use its arithmetic mean value as (X max-ma)/x and (x Xm1n)/
Let the larger value of x be α.

Further, in the present invention, the angle of repose is determined as follows.

■, Angle of Repose Measurement Method Place a glass funnel (with a spout diameter of
0 m, the glass cylinder at the outlet has a diameter of 7 mm, a length of 7 mm, and the total height of the funnel is 57 m).After setting the outlet vertically, the sample collection method according to JIS, -6911-1979, 3, 1 was carried out. Accordingly, the sample at about 300F is gently poured through a glass funnel onto a glass disc. If the sample gets stuck in the glass funnel, use a copper stirring rod with a diameter of 2 fi and a length of about 200 m to remove it. Height h of the mountain formed on the circular table
(e=)' and the angle of repose (θ), θ== t
The angle of repose is obtained from an-1(h), and is the average value of the five values excluding the upper and lower (maximum and minimum) two measured values among the seven measured values.

〔Example〕

Hereinafter, several examples of the present invention will be illustrated in more detail by giving examples as well as comparative examples.

In the following, the test methods and evaluations of automatic metering suitability (powder flowability), preheating tableting suitability, crack resistance, and cold compression tablet strength are as follows.

(1) Randomly collect 5 kg samples according to automatic weighing aptitude knee JIS K6911-1979.This is placed in a hopper with a straight body part of 500 mφ x 100 cod, a conical part height of 500 mm, and a discharge part of 33 mφ x 30 mm with a discharge damper. Pour gently into the center. 100m below the center of the outlet, JISK6911-197
Place the metal graduated cylinder for apparent density measurement specified in step 9, fully open the damper, and fill the graduated cylinder with the material. Once the material is sufficiently filled to allow it to spill over, the damper is closed and the sample in the graduated cylinder is weighed in the same manner as for apparent density determination. By this method, the weight t is continuously measured 50 times (n), and the standard deviation S of these values is taken as the automatic weighing suitability value.

Here, n = 50 i = 1 to 50 yi = weight measurement value of each time (2) 7 = arithmetic mean value of all yi data (2) (2) Approximately 5 yen according to JIS K 6911-1979 Collect samples randomly. This is preheated by high frequency using a high frequency preheater FDP320A made by Fuji Denpa, a polyethylene preheater ring with a diameter of 100 baits x 25 m in height, and a glass fiber reinforced epoxy laminate root (140 x 140 x 2 m). The preheating conditions at this time were a distance between poles of 30 degrees, an output of 2 KW, and a frequency of 62 MHz. The sample was placed in a preheater ring placed on a 130fi laminate plate, flattened, and then preheated by high frequency.

The preheated product obtained by such an operation is promptly removed from the preheater while being placed on the laminate board.

Remove the laminate plate and let the tableted sample (by preheating) fall freely from inside the preheating ring.

The above operation is repeated to determine the number of times of preheating at which the weight of deposits on the preheater ring becomes 52 or more.

(3) A cold-compressed tablet sample with a hardness of 50F was placed in a tablet molding having a cylindrical cavity with a diameter of 50 m and a height of 200 m, and a pressurized cuff was placed.
cp/- for 10 seconds at room temperature to form a tablet. The surface hardness of this tablet was determined using a Percoll hardness meter.

(4) Dust prevention suitability 1007 samples were randomly collected according to JIS K6911-1979. Pour this gently into a cylindrical glass container as shown below. Cylindrical container has an inner diameter of 50fII
1. LJ with a height of 500wm), at the bottom of the container,
Take the No. 2 glass filter, which has a thickness of 5 layers, and put it on.
The shape allows dry air to be blown into the bottom of the container. Dry air is blown for 1 minute at a flow rate of 11/min from the bottom of the container containing the 100f sample. By this operation), the weight loss of the spilled water is determined and the dust prevention suitability is determined.

(5) Collect a sample with a collapse resistance of approximately 1002, and place it in a Rotatub large shaker, J
IS, on a 200φ 80 mesh standard sieve, rotor tube rotation speed 290 times/min, number of blows 156 times/min, total amplitude 28
Sieve for 10 minutes under m conditions.

Next, the weight of the sample on the under-sieve tray was measured, and then the sieve operation was continued for another 6 hours, the weight of the sample on the under-sieve tray was measured again, and the disintegration rate was calculated according to the formula below. ,
This is the collapse resistance value.

Here, WO = total weight of the sample (9) wlOM = sieve fraction is the weight of the sample under the sieve after 10 minutes of operation (2) w6H = sieve fraction is the weight of the sample under the sieve after 6 hours of operation (f) (6) Molded product resistance A bowl with a crack diameter of 6 inches and a weight of 120F was compression molded under the following conditions.

Mold temperature 165℃ (upper mold) 160℃ (lower mold) Pressure 180 kII/, ff
Preheating time: 60 seconds Degassing time: 0.5 seconds Molding time: 60 seconds The bowl formed in this way is subjected to 4 cycles a day, with the next cycle being a - cycle, and the number of cycles and days until cracks appear are determined. .

The crack resistance is displayed as (number of days) - (number of cycles), and for example, 2-3 indicates that cracks occurred on the third cycle on the second day. 'Crack resistance: 3-1
The above is preferable, and 4-1 or more is particularly preferable.

(5) Impact resistance of the molded product Compression molding was carried out under the same conditions as in (4) Cracking resistance of the molded product.

An impact strength test was conducted using the 9-inch flat plate formed in this manner.

First, approximately 909 steel balls are dropped 50 times from a height of 50 crn onto the approximately central portion of the flat plate which is in a face down state. If a crack occurs during that time, record the number of times the steel ball falls until the crack occurs (for example, if a crack occurs on the 35th time, record it as 50 crn - 35 times). 5
If no cracks occur even after dropping 0 times, increase the height by 10α (i.e. from a height of 60cy++), repeat the above experiment, and record the height and number of times cracks occur ( For example, if a steel ball is dropped from a height of 60α,
If a crack occurs on the 25th time, record it as 60-25 times).

Reference example Melamine (Made by Yuka Melamine; Yuka Melamine) 1260
? , 1380 ml of a 37% concentration formalin aqueous solution and 900 ml of water were placed in a flask equipped with a reflux condenser, and F/M=,
The reaction was carried out by heating at 90° C. with stirring under the conditions of 7. When the cloudy point of the melamine resin liquid reaches 60℃, 2f of NaO
H was added and cooled to obtain a melamine resin initial condensate. The white turbidity point, which was used as a measure of the end of the reaction, refers to the temperature at which white turbidity occurs when the m-layer liquid of 5- is sampled, hot water of about 80° C. 45- is added thereto, stirred and cooled.

The melamine resin initial condensate thus obtained (solid general term 5
0 weight) 2500F, valve 460f (approximately 27 weight relative to the total amount of solid content of melamine resin and valve)
After adding and kneading with a kneader, the mixed mixture was dried in a hot air dryer at 90°C for 90 minutes to form a popcorn t-mata.

Titanium oxide 5F is added to this popcorn 5001.

Add 0.5 F of anhydrous 7 tar acid and 2.52 F of zinc stearate and grind for 8 hours in a bot mill to obtain a valve content of 26%.
A melamine resin molding composition powder was obtained.

Example 1 The melamine It@molding composition powder obtained in Reference Example was then heated and kneaded into a melt using a co-rotating twin-screw kneading extruder. The kneading extruder has a shaft diameter of 55φ, L/D=20, and a compression ratio of 2.
．． 0 screw and the composition powder feeding rate was 20
kF/min, a cylinder temperature of 100° C., and a screw rotation speed of 100 rpm to obtain a heat-extruded, kneaded, melt-molded product.

After the kneaded molded product was coarsely crushed, it was crushed using an impact crusher with a screen diameter of 2 mm to obtain a granular melamine resin molding material.

Melamine resin molding powder composition that does not pass through a 24 mesh sieve, passes through a 24 mesh sieve but does not pass a 42 mesh, passes through a 42 mesh sieve but does not pass a 145 mesh, and passes through a 145 mesh sieve weight ratio, angle of repose, and melamine resin molding powder Table 1 shows the test results for the composition's suitability for automatic weighing, suitability for preheating tableting, tablet strength, molded product crack resistance, and molded product impact resistance.

Example 2.3 and Comparative Examples 1 to 5 Melt-molded products were obtained using the kneading extrusion method in the same manner as in Example 1, and granular melamine resin molding materials were produced by changing the coarsening conditions and re-crushing conditions. Moreover, the molding materials of Comparative Examples 1 to 5 were also produced according to this method.

Table 1 shows the particle size, average hardness, hardness variation index, angle of repose, and performance measurement results of these materials.

Examples 4 to 6 and Comparative Examples 6 to 9 In Example 1, L/D1 of the screw of the kneading extruder
Granular melamine resin molding materials were produced in the same manner except that materials with different compression ratios were used.

Table 1 shows the particle size, average hardness, hardness variation index, angle of repose, and performance measurement results of these materials.

Comparative Example 10 Table 1 shows the particle size, average hardness, hardness variation index, angle of repose, and performance measurement results for commercially available granular melamine m+i molding material K (manufactured by Company A).

Claims (2)

[Claims] (1) A granular melamine resin molding material obtained by re-crushing a heated extrusion molded product of a melamine resin molding composition powder, wherein A, the particle size distribution is 100% by weight of the total amount of the molding material;
(a) Less than 3% by weight of materials that do not pass through a 24 mesh sieve, (B) 25 to 60% by weight of materials that pass through a 24 mesh sieve and do not pass through a 42 mesh sieve, (c) Materials that pass through a 42 mesh sieve and do not pass through a 145 mesh sieve. 25 to 60% by weight of those that do not pass through the sieve, (d) 10% or more of those that pass through a 145 mesh sieve, 2
less than 4% by weight, and further, B, the hardness x (kg/cm^2) of the molding material is expressed by the following formula (1).
-α) @x@≦x≦(1+α)@x@ (However, @x@ is the average hardness of the molding material (kg/cm^2
), α is an index representing the range of variation in hardness), when @x@(kg/cm^2) and α are a, 8
A granular melamine resin molding material characterized in that 0≦@x@≦300 b and 0.3≦α≦0.7. (2) The granular melamine resin molding material according to claim (1), wherein the angle of repose of the granular melamine resin molding material is 40° or more and less than 50°.