JPS6010533B2 - Molding resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin composition for molding, and more specifically, the present invention relates to a resin composition for molding, and more particularly, the present invention relates to a resin composition for molding, which has very little sedimentation of filler until the thermosetting resin is cured, and has a uniform filler distribution after curing. The present invention relates to a resin composition for use.

Conventionally, in molding resin compositions, when inserts such as windings are molded, thermal distortion occurs due to temperature changes during curing and use because the resin and the insert have different coefficients of thermal expansion.

For this purpose, a method has been adopted in which an inorganic filler or the like is added to reduce the difference in coefficient of thermal expansion by 4. However, in filler-containing thermosetting resin compositions, sedimentation of the filler occurs before curing due to the difference in specific gravity between the resin and the filler, so the filler distribution always becomes uneven after curing. If the filler distribution becomes uneven, the curing shrinkage rate and ferrohelastic coefficient in the molded product will differ depending on each part, and the residual strain will be the largest especially at the top where the filler content is low, and when the sedimentation becomes large, it will increase from the top. There is a problem that cracks occur. Up to now, methods have been used to increase resin viscosity or shorten curing time in order to prevent filler sedimentation, but these methods significantly reduce workability. Particularly in the molding of large equipment, the above method cannot be adopted because a large amount of resin is handled and workability becomes a problem. As the size increases, the residual strain increases and cracks are more likely to occur, so a method of slowly curing at a low temperature is usually used to reduce the residual strain. This, on the contrary, leads to more sedimentation and is a factor that makes it extremely difficult to prevent sedimentation.
In addition, methods have been used to reduce the sedimentation rate by reducing the particle size of the filler by 4 mm, but conventionally, when fillers with small particle sizes are used, the viscosity of the molding resin composition tends to increase significantly. It was believed that reducing the particle size of the filler would necessarily increase the viscosity. When adding a large amount of filler, it is unavoidable to use one with a fairly large particle size, and when it is necessary to reduce sedimentation of the filler, a small amount of filler with a small particle size is added. To compensate for the increased residual strain, the method used was to make the resin more flexible and increase its elongation at break. however,
If the heat resistance of the resin is increased, the resin generally becomes hard and brittle, so it is necessary to add a large amount of t-filler to minimize the residual strain. Small ones cannot be used, and adding a malleable agent to make them soft is not possible due to heat resistance.

For the above reasons, conventional molding resins for large molds have been limited to Type B or lower. In view of the current situation, the purpose of the present invention is to "improve the above-mentioned problems by reducing the particle size of the filler and making the filler content distribution in the molded product uniform through sedimentation, while also achieving low viscosity and workability." An object of the present invention is to provide an extremely good molding resin composition.The present invention takes the following configuration in order to solve the above problems and achieve the above objects.

That is, "the molding resin composition of the present invention is made of a thermosetting resin and has a substantially particle size of 80 μm or less," and the cumulative weight percentage from the maximum particle size in the RRS particle size diagram is 25% by weight and 75% by weight. It is characterized by being made of an inorganic filler having a particle size distribution in which the slope of a straight line connecting two points of % is 0.9 or less.

In this specification, the RRS grain size diagram refers to the Rosin diagram below.
- A particle size diagram representing a particle size distribution according to Rammler's formula. R (Dp) = 10 × p (1 bDpn) (wherein R (Dp) is the cumulative weight % from the largest grain to the grain Dp (Dp is the particle diameter ~ b and n are constants) and R(Dp) in the formula is also called cumulative residual weight %.

In addition, the slope in the RRS particle size diagram means that the cumulative weight% from the maximum particle size in the RRS particle size diagram is 25% by weight and 75% by weight.
Rosin-Ra is represented by a straight line connecting two points.
It refers to the n value of mmler's formula. Generally, when the filler is crushed, the particle size distribution of the filler is Rosin-Ram
Mler's formula, and is said to form a substantially straight line in the RRS particle size diagram, which is a representation of particle size distribution based on this formula.

The present inventors investigated whether the particle size distribution of various fillers conformed to the above formula or not, and as a result, they found that an almost linear relationship was obtained in the above RRS particle size diagram and that the particle size distribution conformed to the formula.

In addition, as a result of measuring the viscosity of a system in which various fillers were added to a thermosetting resin, the slope of the above RRS viscosity diagram, that is, Ro
It has been found that there is a close relationship between the n value of the sjn-Rammler equation and the viscosity of the molding resin. That is, Ros
When a filler with an in-Rammler equation n value of 1.0 or more is used, the viscosity of the molding resin composition becomes extremely high;
0.

It was found that the increase in viscosity was very small when it was 9 or less.

The larger the n value, the more uniform the particle size, and the smaller the n value, the wider the particle size distribution.Furthermore, some fillers with a maximum particle size of 100 ships or more have an n value of 0.9 or less. However, it has been found that when the maximum particle size is less than 80 mm, the n value of most particles exceeds 1.0.

This may be the reason why it has been believed that the viscosity of the molding resin composition increases when a filler with a small particle size is used.
Regarding fillers with a particle size of less than
The slope of the above straight line of the S grain size diagram, that is, Rosin-R
It was found that the n value of Ammler's equation could be made 0.9 or less, and that the viscosity of the molding resin composition could be lowered by using the parenthesized mixed filler. In other words, ``We have found that even if the particle size is made smaller overall, if the distribution is wide, the viscosity of the composition will be lower.

Furthermore, when a filler is mixed, the plot may deviate from a straight line when plotted on an RRS viscosity diagram.

In this case, it is difficult to calculate the n value of the Rosin-Rammler equation from a mathematical formula, but as a result of various studies,
It has been found that the n value, which is the slope of a straight line connecting two points where the cumulative weight % from the maximum particle size in the RRS particle size diagram is 25 weight % and 75 weight %, can be used instead. In other words, although the n value changes somewhat depending on how the straight line is drawn, the relationship between the n value of the filler and the viscosity of the molding resin composition that is on a straight line in the RRS particle size diagram is different from the relationship between the n value of the filler that is on a straight line in the RRS particle size diagram and the viscosity of the molding resin composition. When plotting the viscosity of the molding resin composition using the agent, the n value is RRS
It was found that the n value almost matched the value determined from the straight line connecting the two points of 25% and 75% by weight on the viscosity diagram. It should be noted that there is almost no practical problem whether the two points of 3 weight % and 7 weight % are connected, or the two points of 2 weight % and 8 weight % are connected. The present invention has been completed based on the knowledge described above, and according to the present invention, even if the particle size of the filler is substantially 80 mm or less, it is possible to appropriately set the crushing conditions and mix fillers with various particle sizes. By the method described above, it is possible to obtain a filler with the above-mentioned slope (n value) of the RRS particle size diagram of 0.9 or less, and by using such a filler, the increase in viscosity of the molding resin composition can be kept relatively small. can do.

Also, when mixing various fillers, the particle size distribution should be RR
A linear relationship may not hold when expressed in the S particle size diagram, but in this case, connect the two points of 25% and 75% of the cumulative weight% from the maximum particle size with a straight line in the RRS particle size diagram. , the same effect can be obtained when the slope of the straight line is 0.9 or less. From this, even if the slope of the RRS particle size diagram is 1.0 or more, two or more fillers with different particle sizes can be mixed according to the present invention, and 25% by weight and 7% of the fillers can be mixed.
An increase in viscosity can be prevented by setting the slope of the straight line connecting two points of 5% by weight to 0.9 or less. Fillers used in the present invention include silica, alumina, aluminum silicate, antimony trioxide, barium carbonate, calcium carbonate, L-ursium sulfate, clay, quartz, fused silica, magnesium carbonate, magnesium oxide, magnesium hydroxide, and hydrated alumina. , magnesium silicate, sericite, sand, zircon, talc, wollastonite,
Examples include dolomite, graphite, ferrite, carbon black, zinc oxide, titanium white, molybdenum disulfide, cement, glass, mica, diatomaceous earth, and the like.

Furthermore, in the present invention, since the wettability between the resin and the filler also has a large effect on the viscosity, the addition of a coupling agent, a surfactant, etc. further enhances the effect. Furthermore, when a very fine filler is used as in the present invention, the elasticity remains the same, but the toughness increases somewhat, that is, the stiffness decreases, and the breaking strength and elongation tend to increase. Therefore, the present invention has the effect of improving mechanical properties.

The present inventors previously discovered that a polyfunctional epoxy compound containing a polyglycidyl ester of a fatty acid in an amount of 10 to 8 wt. , 'b-polyfunctional isocyanate compound 1.
Blended at a ratio of 5 to 5 equivalents, 'c' of the resin composition
．． We have discovered a thermosetting resin composition containing as an essential component a curing catalyst of 0.01 to 1% by weight. The present invention is particularly effective when applied to this type of thermosetting resin composition and applied to heat-resistant large-sized molding. That is, by applying the present invention, the thermal shock resistance is further improved, and molded products such as considerably large windings can be made without cracking. Additionally, as a result of stress analysis, the residual strain can be reduced to approximately 1/a, and the safety factor is 2.
It has been confirmed that the number has more than doubled. In the above-mentioned thermosetting resin composition, the amount of filler added varies depending on the use, but is usually used in an amount within 6% by volume. Especially when it comes to large-sized molding, it is necessary to reduce the coefficient of linear expansion to 4, and to maintain a fairly fluid state during work, which is usually 4.
A range of 0 to 6% applied capacity, preferably 45 to 5% applied capacity is suitable. When molding a large-sized device, the thermosetting resin composition is preferably cured slowly at a relatively low temperature and then sufficiently cured at a high temperature in terms of residual strain and properties after curing.

That is, it is desirable that the first curing is performed at 60 to 130 qo C for 1 to 2 spot hours, and the secondary curing is performed at 130 to 200 qo C for 1 to 2 field hours. In addition to two-stage curing, it is even more desirable to perform curing by dividing the curing temperature into several stages, or to perform curing while gradually increasing the temperature. In addition, when releasing the molding resin composition after curing the molding resin composition, unlike ordinary epoxy resins, the thermosetting resin composition has a tendency to elongate at low temperatures as it hardens. Particularly in the molding of large-sized equipment, it is desirable to allow sufficient curing and slow cooling before releasing from the mold. In order to understand the correlation between particle size distribution and viscosity when the inorganic filler used in the present invention is blended into a fluid, propylene glycol was used as a model fluid, and the viscosity when the filler was blended into it was measured. .

The results are shown in FIG. Figure 1 is a diagram in which the horizontal axis is the filler amount and the volume ratio of the fluid, and the vertical axis is the viscosity on a 10 ta scale. According to Figure 1, the relationship between the two is a straight line, and the slope is It was found that the gradients of the RRS particle size diagrams of the fillers were in ascending order.

Note that F-2, F-5, and F-6 in the figure are experimental examples using fillers shown in Examples below. Generally, the filler is RR
The smaller the slope of the S particle size diagram, the lower the viscosity of the fluid blended with it, and this shows that the filler of the present invention can be applied to various resins.

The molding resin composition of the present invention exhibits excellent effects due to the above-mentioned structure and action, uses a filler with a relatively small particle size, and does not cause sedimentation of the filler during molding. Uniform molded products can be easily produced without increasing viscosity.

The molding resin composition of the present invention can be particularly advantageously applied to heat-resistant large-scale molding, such as molding large-sized electrical windings, and has excellent physical properties such as mechanical strength without causing cracks and reducing residual strain. Since it is possible to make molded products that have the same properties, it has extremely high utility value from the point of view of safety. Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited by these in any way.

Examples 1 to 3 and Comparative Examples 1 to 3 Fused quartz powder having various particle size distributions shown in FIG. 2 and Table 1 was used as a filler, and a composition shown in Table 1 was used as a thermosetting resin. .

Figure 2 shows RR for fillers made of various fused silica powders.
S particle size diagram, 2 of the cumulative weight % from its maximum particle size
The slope of the straight line connecting the two points of 5% by weight and 75% by weight, that is, the n value of the Rosin-Rammler equation, is F-1
Filler is 0.72, F-2 is 0.72, F-3 is 0.
75, F-4 is 0.75, F-5 is 0.94, F-6 is 1.02, F-7 is 0.99, F-8 is 1.22, and the filler of F-4 is Except for the other fillers, the particle size is substantially less than 80 mm.

The above molding resin composition was mixed at 80 qo, degassed, and then poured into a tin mold of 50 x 50 x 100 ribs (height) in small increments, heated at 110 pm for 5 hours, then heated at 180 q.
It was cured for 1 hour at o.

Table 1 shows the relationship between the viscosity at 80 oo and the molding resin composition in this case.

Table 1 (1) Pisphenol A type epoxy resin (epoxy equivalent: 176) (2) Digrindyl ester of linoleic acid dimer (sodifying agent) (3) Modified liquid diphenylmethane disocyanate (MDI) or The filler distribution in the molded product after curing is shown in Figure 3, which shows that the molded product was cut into pieces with a thickness of 1 foot, and each was heated at 600 qo for 1 hour, then at 80 qo.
The amount of filler in each part was determined from the change in weight before and after incineration for one hour.

The following can be seen from this result. That is, F-1 to F
In F-3 (Examples 1 to 3), the viscosity is low and the filler amount distribution is uniform as shown in Table 1 above, but F-4 (Comparative Example 4: A filler with a viscosity greater than 80 μm is used) ), the viscosity was low, but it was observed that there was a considerable difference in filler content distribution between the upper and lower parts of the molded product, and F-5 to F-6
In Comparative Examples 5 and 6, the viscosity increased significantly and the workability was poor, but the filler content distribution was relatively good.
Therefore, it is clear that the viscosities of Examples 1 to 3 are lower than those of Comparative Examples 1 to 3, and that the filler content distribution in the molded articles according to the present invention is uniform and there is little sedimentation. Examples 4 to 6 and Comparative Examples 4 to 6 A system in which the same raw materials as in the above Examples were used and the content of filler (fused silica powder) was varied, with very little sedimentation of the filler and cases with a lot of sedimentation. The differences in thermal shock resistance and mechanical properties were compared using C-shaped washers. The composition ratios are shown in Table 2. The injection work was carried out in the same manner as in Example 1 above at 80 qo, and at 80°C for 1 hour.
It was cured under the conditions of 8 hours at 140qo and 1 feeding time at 180qo. Table 2 (5) Novolac type Evoquin resin (Evoxy equivalent: 176
) (6) Linoleic acid dimer diglycidyl esbre (
(7) Modified liquid diphenylmethane diisocyanate (MDI) The thermal shock resistance test was carried out by fixing the molded resin 3 shown in Fig. 4 to the C-shaped washer 1 with a spacer 2. 1 using a C-shaped washer measuring device and a thermal shock tester.
The test was conducted under heat cycle conditions in which the cycle was 180 qo/1 hour on the high temperature side, 2 minutes at room temperature, 1 hour on the low temperature side, 2 minutes at room temperature, and the low temperature side was lowered by 10 qo from 0°C to -70°C.

Thermal shock resistance was evaluated based on the low temperature at which cracks occurred. In addition, the mechanical properties were examined using a test piece of 13 x 5 x 12 capes under the conditions of a measurement temperature of 180 oo, a span of 8 ridges, and a bending speed of 2 ribs/min. The measurement results are shown in Table 3. From the results shown in Table 3 and above, it can be seen that the physical properties of the molding resin composition of the present invention are excellent regardless of the blending ratio of the filler.

Example 7 and Comparative Examples 7 to 8 The same test as in Example 1 was conducted using resins having the following compositions and changing the additive filler, and the differences in viscosity at 100 qo were compared.

The results are shown in Table 4. 3,4-epoxycyclohexylmethyl-(3,4-epoxy)cyclohexanecarboxylate 30 tapisphenol A type epoxy resin (epoxy equivalent 410)
70 Ta vinyl cyclohexene dioxide 20 Ta methyltetrahydrophthalic anhydride 100 Ta filler
360 evening table 4 (8)
Example 8 and Comparative Example 9 The molding resin compositions of Example 1 and Comparative Example 1 were used to mold a coil having the shape shown in Figure 5, and a heat cycle test was conducted. .

In Fig. 5, the coil material 4 is aluminum foil (0.5 [, 10
00, 130 turns), and the interstage material was a film formed by coating silicone resin on glass cloth and curing it. The molding conditions for Western resin 5 were as follows: After drying at 150° C. for 5 hours, the resin was cooled to 80° C. under reduced pressure, and then injected under reduced pressure. (0.05 kite day #
) The curing conditions were 1 hour at 11000 (primary curing), 1
Curing was carried out in two batches at 603○ for 15 hours (secondary curing). Four molded coils were made, two of which were first cured and cooled to 80°C before mold release, and the other two were secondary cured and then slowly cooled to 50q0 before mold release. Ta. The heat cycle was carried out 100 times, with one cycle consisting of 18,000 degrees, 7 hours, and -30 degrees, 7 hours. The results are shown in Table 5. 5 From the results shown in Table 5, it was found that the cured product after primary curing was quite brittle and easily cracked even when subjected to a large impact.

In addition, in Comparative Example 9, cracks occurred on the upper surface of the coil both after primary curing and after secondary curing, and it was observed that cracks occurred in areas with low filler content due to sedimentation of filler. . Examples 9 to 12 and Comparative Examples 10 to 12 F-7 (n=0
．． A mixed filler was prepared using 99) and F-8 (n=1.22), and the viscosity of the molding resin composition having the composition shown in Table 6 was measured.

The results are shown in Table 6. Table 6 (Note) Resin composition Novolac type epoxy (epoxy equivalent: 174) 50 Diglycidyl ester of talinoleic acid dimer 50 Modified liquid diphenylmethane diisocyanate 140 Polyglycidoxytrimethoxysilane 2.5 From this result, n value It can be seen that even if the filler has a high particle size, the viscosity can be significantly lowered by mixing two or more fillers with different particle sizes.

In the Examples and Comparative Examples, the relationship between the n value and the relative viscosity (the ratio of the viscosity of the filler-added system to the viscosity of the filler-free system) is summarized in FIG. 6.

From this result, the slope (n value) of the RRS particle size diagram is 0.9
It can be seen that the relative viscosity increases significantly when the temperature exceeds this value.
Examples 13 to 17 and Comparative Examples 13 to 16 Crystalline silica powder fillers F-9 (n = 1.7), F-10 (n = 1.55) and F-11 (n=1.2) and a mixed filler thereof were prepared, a molding resin composition was prepared using the same thermosetting resin as in Example 9, and the viscosity was measured.

A total of 357 fillers were used in each case. The results are shown in Table 7. Table 7. From this result, even when changing the type of filler,
It can be seen that those with an n value of 0.9 or less have a low viscosity, and even those with a high n value can lower the n value and viscosity by mixing them.

As described above, according to the present invention, by using a filler with a small particle size and utilizing it in an appropriate particle size distribution, the increase in viscosity of a resin composition for molding can be reduced, and uniformity is advantageously achieved, which is the key to improving physical properties. The role of the present invention in this technical field is extremely important.

Brief Description of the Drawings The drawings show specific examples of the present invention and various tests and results. Figure 1 is a graph showing the relationship between the amount of the filler of the present invention added to the model fluid and the viscosity. 2 and 7 are RRS particle size diagrams of the filler used in the present invention, FIG. 3 is a graph showing the filler distribution in the molded article in the present invention, and FIG. is a perspective view of a crack resistance test piece used in the present invention,
FIG. 5 shows the structure of the winding wire used in the tests of the present invention, and FIG. 6 is a graph showing the relationship between the n value and the relative viscosity in a specific example of the present invention.

In Figures 4 and 5, 1...C-shaped washer, 2...Subesa, 3...Western type resin, 4...Coil (aluminum foil) + inter-column paper), 5...
...Shuang type resin.

7th figure O figure Figure 2 Figure 3 Ikumu diagram 5th figure 6th figure

Claims (1)

[Claims] 1. In a molding resin composition formed by blending a thermosetting resin with an inorganic filler, the thermosetting resin has (a) 10 to 8
1 equivalent of a polyfunctional epoxy compound containing 0% by weight of a polyglycidyl ester of fatty acid and 1.5 to 5 equivalents of a polyfunctional isocyanate compound (b) are blended, and (a) and (
The curing catalyst is blended in an amount of 0.01 to 10% by weight based on the total amount of b), and the inorganic filler has a particle size of substantially 80μ or less, and has a particle size of 0.01 to 10% by weight based on the total amount of b). A molding resin composition having a particle size distribution in which the slope of a straight line connecting two points of 25% and 75% by weight of the cumulative weight% of is 0.9 or less.