JPH06145471A - Molding material of resol type phenol resin - Google Patents

Abstract

PURPOSE:To obtain a molding material of resol type phenol resin suitable for producing thin moldings, moldings of complicated shape and moldings of multi- cavity mold. CONSTITUTION:100 pts.wt. molding material of resol type phenol resin is blended with 10-100 pts.wt. cured material of melamine resin as a filler. Molding can be carried out in the absence of ammonia by a resol type phenol resin. Moldability is improved by blending of the cured material of melamine resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resol type phenol resin molding material used as a molding material for injection molding and the like.

[0002]

2. Description of the Related Art When a phenol resin composition is used as a molding material for injection molding or the like, a novolac type phenol resin is often used. The novolac type phenol resin is cured by using a curing agent such as hexamethylenetetramine. There is a need. However, since hexamethylenetetramine decomposes into ammonia during the reaction, it may deteriorate the working environment due to the smell of ammonia, or the mold may be corroded and clouded. -In the case of molding an electronic component, ammonium ions and the like are contained as impure ions in the molded product, which may adversely affect the electrical characteristics.

Therefore, when molding electric / electronic parts such as a coil bobbin, a power supply case, and a micro switch,
A molding material using a resol-type phenol resin as a non-ammonia phenol resin is used.

[0004]

The electric and electronic parts such as the coil bobbin, the power supply case, and the micro switch have become thin, thin and small in size due to the recent combination of parts, and the productivity is improved. Therefore, it is required to carry out molding of a large number of pieces. However, when molding a large number of thin-walled and complicated-shaped molded products, various problems occur in moldability. That is, studies have been made to adjust the fluidity of the molding material to improve the continuous stability and moldability of molding, but if the molding material is hard (the monohole flow described below is large for about 100 seconds or more, spiral The flow is as small as 45 cm or less),
The fluidity deteriorates and the cavity on the side closer to the sprue is filled, but the ability to fill the cavity on the far side deteriorates.
Also, the parting line (P
L) causes a large amount of burrs and lacks in dimensional stability of the molded product, and on the contrary, softens the molding material (the monohole flow described later is small and the spiral flow is large) to improve fluidity. If it is improved, problems such as flowing from the sprue to a cavity far away but impairing the filling of details and slowing the curing and lowering the thermal rigidity of the molded product occur.

The present invention has been made in view of the above points, and an object of the present invention is to provide a resol-type phenol resin molding material suitable for molding thin-walled, complex-shaped, multi-cavity molded articles. is there.

[0006]

The resole type phenolic resin molding material according to the present invention comprises 100 parts by weight of a resole type phenolic resin composition and 10 to 100 parts by weight of a cured melamine resin as a filler. It is characterized by. Further, in the present invention, the cured melamine resin preferably has a DSC curing degree of 60 to 100% and an average particle diameter of 20 to 130 μm.

The present invention will be described in detail below. As the melamine resin cured product, a product obtained by crushing a melamine resin molded product can be used, and it is preferable to use a discarded product such as a defective product or burr that appears in the molding process for recycling waste plastics. . The cured melamine resin preferably has a DSC curing degree of 60 to 100%. DSC (Differential Sc)
The anning calorimeter: a scanning differential calorimeter) changes the temperature of the sample and the reference substance (alumina, etc.) at a constant rate, and changes the energy input ΔQ to the two.
Is a device adapted to measure as a function of temperature T,
As one of the thermal analysis methods, it is possible to quantify the amount of absorption and heat generation of a substance with a DSC curve more accurately than with DTA. The exothermic peak of the DSC curve becomes smaller as the degree of cure of the resin increases, and the exothermic peak disappears when completely cured. Therefore, the exothermic amount of the exothermic peak of the cured product is divided by the exothermic amount of the exothermic peak of the uncured resin. The DSC degree of cure can be determined as a percentage of the value obtained by subtracting from 1. When the DSC degree of curing of the melamine resin curing agent is less than 60%, the melamine may react with the phenol resin more than acting as a filler and may lower the fluidity. Further, the cured melamine resin has an average particle size of 20 to
Particles in the range of 130 μm are preferred. If the average particle size of the cured melamine resin is less than 20 μm, it becomes powdery and difficult to handle, such as automatic weighing becomes difficult, and if the average particle size exceeds 130 μm,
The particles can become too large to plug the mold gate and prevent the molding material from being delivered to the cavity.

The resol type phenol resin composition is a resol type phenol resin containing inorganic fillers such as alumina, silica, calcium carbonate, talc, clay, barium sulfate and aluminum hydroxide, and curing aids such as calcium hydroxide and magnesium hydroxide. , A zinc stearate, a magnesium stearate, a carnauba wax, and other release agents, and other pigments, flame retardants, modifiers, and the like. By blending the cured product as a filler, a resol type phenol resin molding material can be prepared. The blending amount of the cured melamine resin is set in the range of 10 to 100 parts by weight with respect to 100 parts by weight of the resol-type phenol resin composition. If the blended amount of the cured melamine resin is less than 10 parts by weight, the effect of enhancing the moldability by blending the cured melamine resin as a filler cannot be sufficiently obtained. On the other hand, if the blended amount of the cured melamine resin is more than 100 parts by weight, the amount of the filler will be excessive and the fluidity will be lowered, and the moldability will be rather deteriorated.

The resole-type phenol resin molding material prepared as described above is used for injection molding and the like, and does not require a curing agent such as hexamethylenetetramine as in the case of novolac-type phenol resin. ,
Non-ammonia molding can be performed.

[0010]

The invention will now be illustrated by the examples. (Example 1) 45 parts by weight of a resol type phenol resin, 10 parts by weight of talc as an inorganic filler, 3 parts by weight of calcium hydroxide as a curing aid, 2 parts by weight of zinc stearate as a release agent, other pigments and difficult A resol type phenolic resin composition was prepared by blending 5 parts by weight of a flame retardant and a modifier.
And, with respect to 100 parts by weight of this resol type phenol resin composition, the degree of DSC curing is 60% and the average particle diameter is 20.
A resol-type phenol resin molding material was prepared by mixing 10 parts by weight of a powder of the melamine resin cured product having a size of μm, and mixing and kneading the mixture.

(Examples 2 and 3) As the melamine resin cured product, one having a DSC curing degree and an average particle size shown in Table 2 was used, and the compounded amount shown in Table 1 was added to the resol type phenol resin composition. A resol type phenol resin molding material was prepared. (Comparative Example 1) A resol-type phenol resin molding material was prepared without blending a melamine resin cured product.

Comparative Example 2 A cured melamine resin having a DSC curing degree and an average particle diameter shown in Table 1 was blended in a resol type phenol resin composition in an amount of 120 parts by weight to prepare a resol type resin. A phenolic resin molding material was prepared. (Comparative Examples 3 to 5) Instead of the cured melamine resin, Table 2
A resol type phenol resin molding material was prepared by blending a phenol resin cured product having a DSC curing degree and an average particle diameter shown in (1) as a filler. Here, in Comparative Examples 3 to 5, the characteristics of monohole flow and spiral flow were changed by changing the kneading conditions at the time of preparing the resin molding material.

The monohole flow and spiral flow of the resole type phenolic resin molding materials prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were measured. The measurement of the monohole flow was carried out by using an extrusion tester, placing 40 g of the sample in a mold provided with a monohole, and heating at a temperature of 120 ± 2 ° C. and a molding pressure of 62 kg / cm ^{2 and} a pressure of 50 mmφ.
The sample was extruded from the monohole by the plunger of No. 1 and the time taken for the sample to completely flow out in the mold was measured. For spiral flow measurement, use EM
In accordance with the MI1-60 standard, a sample temperature of 6 g is applied to a mold temperature of 15
This was performed by measuring the length of the molded product that flowed into the spiral flow mold when transfer molding was performed under the conditions of 0 ° C., molding pressure of 90 kg / cm ² and 90 seconds. The results are shown in Tables 1 and 2.

Using these resol type phenolic resin molding materials, a pressing pressure of 150 tons, a cylinder temperature of 80 ° C. at the front, 60 ° C. at the rear, and a mold temperature fixed side 180 to 190.
℃, movable side 175-185 ℃, injection pressure gauge 130k
g / cm ² , screw rotation speed 45 rpm, injection time 5
Second, the curing time was 20 seconds, and the coil bobbin was injection molded under the conditions of the gate side gate. The moldability during this molding was evaluated, and the results are shown in Tables 1 and 2.

[0015]

[Table 1]

[0016]

[Table 2]

In Tables 1 and 2, the "continuity" of moldability is a measurement of whether molding is possible continuously, and the one in which molding is stopped by cylinder curing in 1 hour of continuous molding is "x". “A” was evaluated when the molding was stopped for 1 hour or more and less than 8 hours, and “◯” was evaluated when the molding was continuously performed for 8 hours or more. The "fillability" of the moldability was evaluated by observing the fillability of the pin press-fitting portion of the coil bobbin. All of the examples were good, but all of the comparative examples 1, 3 and 4 were filled in all the cavities, but the filling property of the details was poor and a thin wall was generated. In the cavities, the cavities closer to the sprue were filled with details, but the distant cavities did not flow and did not fill the cavities. In addition, for molding thermosetting resin, it is necessary to always provide an air vent in the mold to release air and curing reaction gas in the cavity, but if the burr of the air vent is not released every time in continuous shots, the air vent The effect of degassing from is lost, and gas remains in the molded product resulting in lack of thickness. The moldability "burr releasability" is a measure of whether or not burrs are released from this air vent. "○" means that the burrs are released every time, and "sometimes" does not. “Fair” was evaluated, and those that were not released were evaluated as “x”. The "uniformity of burr" was evaluated as "○" when the burr was evenly spread in each cavity, and "x" when the burr generated in the "cavities" varied. "Thermal rigidity" is "○" when there is rigidity immediately after molding and the sprue can be sandwiched by the automatic take-out chuck to take out the molded product. Those that could not be evaluated were evaluated as "x".

As can be seen from Table 1 of each Example and Table 2 of each Comparative Example, a cured melamine resin was used as a filler in an amount of 10 to 10.
It is confirmed that the moldability of each of the examples compounded in the range of 100 parts by weight is improved.

[0019]

As described above, according to the present invention, 100 parts by weight of the resol-type phenol resin composition is mixed with 10 to 100 parts by weight of the cured melamine resin as a filler. In addition to being capable of being molded, the compoundability of the cured melamine resin is enhanced to enhance the moldability, and it is possible to mold thin-walled, complex-shaped, multi-cavity molded products with good moldability.

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[Procedure amendment]

[Submission date] March 8, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

[0004]

The electric and electronic parts such as the coil bobbin, the power supply case, and the micro switch have become thin, thin and small in size due to the recent combination of parts, and the productivity is improved. Therefore, it is required to carry out molding of a large number of pieces. However, when molding a large number of thin-walled and complicated-shaped molded products, various problems occur in moldability. In other words, although studies have been conducted to adjust the fluidity of the molding material to improve the continuous stability and moldability of molding, use a molding material with a low flow rate.
If it is set to a large value (the monohole flow described later is large for about 100 seconds or more and the spiral flow is small for about 45 cm or less), the fluidity deteriorates and the cavity near the sprue is filled, but to the cavity on the far side. <br filling becomes poor, and burr parting line (PL) is increased occurs to problems such as dimensional stability of the molded article lacks occurs at around the sprue, the molding material at a high flow in the opposite /> (Small monohole flow described later is small, spiral flow is large), and if the fluidity is improved, it will flow from the sprue to the cavity farther, but the filling property into the details will deteriorate,
Further, there is a problem that the curing is delayed and the thermal rigidity of the molded product is lowered.

Claims (2)

[Claims] 1. A resol type phenolic resin composition 100.
10 to 1 parts by weight of a cured melamine resin as a filler.
A resol-type phenol resin molding material characterized by being mixed in an amount of 00 parts by weight. 2. The cured melamine resin has a DSC curing degree of 6.
0 to 100% with an average particle size of 20 to 130
The resole-type phenolic resin molding material according to claim 1, which has a thickness of μm.