JP2022114531A - Thermosetting resin composition - Google Patents

Abstract

To provide a resin material which has reduced dimensional change and is lightweight, and therefore can be suitably used as a substitute for metallic parts.SOLUTION: A thermosetting resin composition comprises a thermosetting resin and an organic filler, where a cured material of the thermosetting resin composition has a relative density of 1.30 to 1.75 inclusive, and a dimensional change rate of the cured material of the thermosetting resin composition, measured under the following condition, is 0.15% or less. (Condition): the thermosetting resin composition is molded at a mold temperature of 175°C for a cure time of 5 minutes under a molding pressure of 30 MPa to obtain a molding having a dimension of 80 mm×50 mm×5 mm (t0); thereafter, the molding is post-cured at 220°C for 3 hours; the molding after curing is allowed to stand at 120°C for 250 hours and a thickness (t1) after processing is measured; and a dimensional change rate is obtained by the following formula (1): dimensional change (%)=[(t0-t1)/t0]×100.SELECTED DRAWING: None

Description

The present invention relates to thermosetting resin compositions.

Phenolic resin molding materials are used as substitute materials for metal parts in various fields because of their excellent heat resistance and relatively good dimensional stability. In the field of automobiles as well, the use of resin for various parts is being promoted in response to the growing demand for smaller, lighter, and lower costs. In particular, car body parts, which were mainly made of metal in the past, are now being replaced by parts made of resin, and parts of various shapes are being molded. For example, Patent Document 1 discloses a phenolic resin molding material containing inorganic fibers such as glass fibers.

Japanese Patent Application Laid-Open No. 2005-247908

However, in the case of resin composite materials containing inorganic fillers, although the use of inorganic fillers can improve the strength and rigidity of the resin composite material and reduce dimensional changes, the higher the amount of inorganic fillers, the more the resin obtained. In some cases, the specific gravity of the composite material increased.

The present invention has been made in view of the above problems, and an object thereof is to provide a resin material which is reduced in dimensional change and light in weight, and which can be suitably used as a substitute for metal parts.

According to the invention,
a thermosetting resin;
A thermosetting resin composition comprising an organic filler,
The specific gravity of the cured product of the thermosetting resin composition is 1.30 or more and 1.75 or less,
A thermosetting resin composition is provided in which a cured product of the thermosetting resin composition has a dimensional change rate of 0.15% or less as measured under the following conditions.
(Conditions) The thermosetting resin composition is molded at a mold temperature of 175° C., a curing time of 5 minutes, and a molding pressure of 30 MPa to obtain a molded body having dimensions of 80 mm×50 mm×5 mm (t0). After that, it is post-cured at 220° C. for 3 hours. The molded article after curing is allowed to stand at 120° C. for 250 hours, and the thickness (t1) after the treatment is measured. The dimensional change rate is obtained from the following formula (1).
Dimensional change rate (%) = [(t0-t1)/t0] x 100

ADVANTAGE OF THE INVENTION According to this invention, the resin material which has a reduced dimensional change and is lightweight, and therefore can be suitably used as a substitute for metal parts is provided.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. In this specification, the notation "a to b" in the description of numerical ranges means "a or more and b or less" unless otherwise specified. For example, "5 to 90% by mass" means "5% by mass or more and 90% by mass or less".

(Thermosetting resin composition)
The thermosetting resin composition of the present embodiment is, for example, a material for obtaining a resin molded product that can be used as a substitute for metal parts used as automobile parts, electronic equipment parts, and household appliance parts. The thermosetting resin composition of this embodiment contains a thermosetting resin and an organic filler.

The cured product of the thermosetting resin composition of the present embodiment has a specific gravity of 1.30 or more and 1.75 or less. Moreover, the dimensional change rate of the cured product of the thermosetting resin composition of the present embodiment measured under the following conditions is 0.15% or less.
(Conditions) The thermosetting resin composition is molded at a mold temperature of 175° C., a curing time of 5 minutes, and a molding pressure of 30 MPa to obtain a molded body having dimensions of 80 mm×50 mm×5 mm (t0). After that, it is post-cured at 220° C. for 3 hours. The molded article after curing is allowed to stand at 120° C. for 250 hours, and the thickness (t1) after the treatment is measured. The dimensional change rate is obtained from the following formula (1).
Dimensional change rate (%) = [(t0-t1)/t0] x 100

The thermosetting resin composition of the present embodiment is excellent in lightness because the cured product thereof has a relatively low specific gravity. In addition, the cured product of the thermosetting resin composition of the present embodiment exhibits reduced dimensional change when exposed to a high-temperature environment. Therefore, the thermosetting resin composition of this embodiment can be suitably used as a metal substitute material.

In one embodiment, the specific gravity of the cured product of the thermosetting resin composition can be 1.35 or more and 1.70 or less, preferably 1.35 or more and 1.65 or less, more preferably It is 1.35 or more and 1.62 or less.

In one embodiment, the dimensional change rate of the cured product of the thermosetting resin composition measured under the above conditions can be 0.14% or less, preferably 0.13% or less, More preferably, it is 0.12% or less.

The specific gravity and dimensional change rate of the cured product of the thermosetting resin composition of the present embodiment can be controlled by adjusting the type of each component used for this, the amount thereof, curing conditions, and the like. , the particle size, particle size distribution, and compounding amount of the organic filler used, the type of phenolic resin, and the type and particle size of the inorganic filler used together with these. Components used in the thermosetting resin composition of the present embodiment are described below.

(Thermosetting resin)
Thermosetting resins used in the thermosetting resin composition of the present embodiment include novolac-type phenolic resins such as phenolic novolac resin, cresol novolac resin, and bisphenol A novolak resin; unmodified resol phenolic resin, tung oil, and linseed oil. , resol-type phenolic resins such as oil-modified resol phenolic resins modified with walnut oil; bisphenol-type epoxy resins such as bisphenol A epoxy resin and bisphenol F epoxy resin; Epoxy resins such as biphenyl-type epoxy resins and tris(hydroxyphenyl)methane-type epoxy resins; resins having a triazine ring such as urea (urea) resins and melamine resins; unsaturated polyester resins, bismaleimide resins, polyurethane resins, diallyl phthalate resins , silicone resins, resins having a benzoxazine ring, cyanate ester resins, and the like.

(organic filler)
The thermosetting resin composition of this embodiment contains an organic filler. The organic filler lowers the specific gravity of the resulting cured product of the thermosetting resin composition without impairing the mechanical strength, and reduces dimensional change at high temperatures. Organic fillers used in the thermosetting resin composition of the present embodiment include cured thermosetting resins, heat-resistant thermoplastic polymer fine particles, and elastomers.

Examples of cured thermosetting resins include cured phenol resins, cured polyimide resins, cashew dust, and cured epoxy resins. Examples of heat-resistant thermoplastic resin polymer fine particles include nylon fine particles. Elastomers include polyvinyl butyral, nitrile butadiene rubber, and the like. An organic filler may be used individually by 1 type, and may be used in combination of 2 or more type. Among them, it is preferable to use a cured phenol resin as the organic filler from the viewpoint of high heat resistance and low thermal expansion.

The organic filler used in the thermosetting resin composition of this embodiment may be spherical powder, amorphous powder, or a combination thereof. A spherical powder means a spherical body obtained by rounding the corners of a powder particle. In addition, irregularly shaped powder refers to powder that does not have a constant shape, such as crushed flakes, plates, scales, needles, and the like.

When the organic filler is at least one of spherical powder and amorphous powder, the filling state in the thermosetting resin composition can be uniform dispersion or close-packing. Furthermore, in applications where the cured product of the thermosetting resin composition is used by joining it to a metal member, it is possible to design the compound so that a part of the organic filler is exposed from the resin. The formed surface unevenness can improve the bonding strength to the metal member.

The average particle size D50 of the organic filler is, for example, 0.1 μm or more and 600 μm or less. The upper limit of the average particle diameter D50 of the organic filler is preferably 500 μm or less, more preferably 400 μm or less, even more preferably 300 μm or less, still more preferably 200 μm or less, and particularly Preferably, it is 100 μm or less. The lower limit of the average particle size D50 of the organic filler is preferably 0.5 µm or more, more preferably 1.0 µm or more, and even more preferably 1.2 µm or more. When the average particle diameter D50 of the organic filler is within the above range, the organic filler is appropriately filled in the resin, and the cured product of the obtained thermosetting resin composition has both high mechanical strength and lightness. can have

Here, when the organic filler is spherical powder, the diameter (outer diameter) is defined as the particle size, and when the organic filler is amorphous powder, the longest part of the shape is defined as the particle size. In the present specification, the average particle diameter D50 is also referred to as the median diameter. It refers to the diameter (D50).

The content of the organic filler in the thermosetting resin composition of the present embodiment can be appropriately selected according to the application of the thermosetting resin composition. , 5% by volume or more and 50% by volume or less. When the content of the organic filler in the thermosetting resin composition is within the above range, the resulting cured product of the thermosetting resin composition has reduced dimensional change in a high-temperature environment and improved lightness. can be

(Inorganic filler)
In one embodiment, the thermosetting resin composition may contain an inorganic filler. A fibrous filler or a powdery filler can be used as the inorganic filler.

Examples of fibrous fillers that can be used include glass fiber, wollastonite fiber, carbon fiber, and plastic fiber. Aramid fibers (aromatic polyamide), for example, are used as plastic fibers. Inorganic fibers such as basalt fibers and metal fibers such as stainless steel fibers can also be used as fibrous fillers.

Among these, glass fiber, wollastonite fiber, and carbon fiber, or a combination thereof, are used because they can increase the mechanical strength of the molded article and also contribute to the weight reduction of the molded article. is preferred. When glass fiber is used as the fibrous filler, specific examples of glass constituting the glass fiber include E glass, C glass, A glass, S glass, D glass, NE glass, T glass, and H glass. Among these, E glass, A glass, T glass, or S glass is preferable. By using such a glass, it is possible to achieve high elasticity of the glass fiber reinforced material and to reduce the coefficient of thermal expansion of the obtained molded product.

As the carbon fiber used as the fibrous filler, for example, a high-strength carbon fiber with a tensile strength of 3500 MPa or more and a high-elasticity modulus of 230 GPa or more are used. Either polyacrylonitrile (PAN)-based or pitch-based carbon fibers may be used, but PAN-based fibers are preferred because of their high tensile strength.

Examples of powdery fillers that can be used include glass beads, glass powder, calcium carbonate, magnesium carbonate, silica, aluminum hydroxide, diamond powder, fluororesin powder, zircon powder, mica, and clay.

When the thermosetting resin composition of the present embodiment contains an inorganic filler, the amount thereof can be selected according to the application. It can be vol% or less. If the content of the inorganic filler in the thermosetting resin composition is within the above range, the resulting cured product of the thermosetting resin composition does not suffer from a decrease in mechanical strength, and the dimensions in a high-temperature environment are maintained. Variation can be reduced and lightness can be improved.

(other ingredients)
The thermosetting resin composition of the present embodiment may contain various other components depending on its use within a range that does not impair the effects of the present invention. Other ingredients include, but are not limited to, coupling agents, flame retardants, colorants, release agents, and the like.

(Method for producing thermosetting resin composition)
The thermosetting resin composition of the present embodiment can be produced by mixing the above components by known means. For mixing, a method of mixing the above components or a method of adding the above components to an organic solvent and mixing can be used.

When mixing, a kneading device such as a pressure kneader, a roll, a co-kneader, a twin-screw extruder or a hot plate can be used, and the mixture can be heated, melted and kneaded at a temperature lower than the temperature at which the mixture hardens. The specific heating temperature for heating varies slightly depending on the selected composition, but is preferably about 50 to 130°C. A thermosetting resin composition is obtained by such mixing. The thermosetting resin composition can be provided in the form of powder, granules, tablets, plates, blocks, sheets, and the like. The form of the thermosetting resin composition can be appropriately selected depending on the application for which it is used.

When an organic solvent is used in producing the thermosetting resin composition, examples of the organic solvent include methanol, ethanol, propanol, butanol, methyl cellosolve, acetone, methyl cellosolve, methyl ethyl ketone, methyl isobutyl ketone, Examples include, but are not limited to, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, quinoline, cyclopentanone, xylene, m-cresol, chloroform, and the like. An organic solvent may be used individually by 1 type, and may be used in combination of 2 or more type.

(Molded body)
A molded article can be produced by curing the thermosetting resin composition of the present embodiment. For example, using the above-described thermosetting resin composition and an appropriate mold, a molded article (cured product of the thermosetting resin composition) can be produced by a method such as transfer molding, compression molding, or injection molding. .

The molded article made of the cured product of the thermosetting resin composition of the present embodiment can be applied to applications such as semiconductor parts, aircraft parts, automobile parts, industrial machine parts, electronic parts, electrical parts, and mechanical parts. can be done.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than those described above can also be adopted.

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited to these.

<Preparation of organic filler>
(Preparation Example 1)
1000 parts by mass of phenol, 1120 parts by mass of a 37% formaldehyde aqueous solution, 200 parts by mass of a 2% hydroxyethyl cellulose aqueous solution, 41 parts by mass of ethylene glycol, and 235 parts by mass of pure water were prepared as raw material components for a mixed liquid. Next, the raw material components were put into a reaction vessel and uniformly mixed to prepare a mixed liquid. Next, in order to react phenol with formaldehyde, 270 parts by mass of a 33% triethylenetetramine aqueous solution as a basic catalyst was added to the mixed solution at a sequential addition temperature of 40° C. over a period of 60 minutes, followed by mixing. The liquid was reacted at a reaction temperature of 60° C. for 1 hour, then the mixed liquid was heated to 100° C. and reacted for 6 hours. The reaction between phenol and formaldehyde was carried out while stirring the mixture. This produced suspended particles of phenol and formaldehyde.
Then, the reaction liquid was cooled to a temperature of 50° C. and sieved with a wire mesh to obtain suspended particles that did not pass through the sieve.
Next, the obtained suspended particles were dispersed in 1,140 parts by mass of pure water, and washing was repeated five times with a wire mesh having an opening of 100 μm to remove the suspended particles that had passed through the wire mesh. The suspended particles washed were 1140 parts by mass. As a result, hydroxyethyl cellulose and ionic impurities on the surface of the suspended particles were washed.
The resulting suspended particles were then dried. Drying was performed using a conical ribbon mixing/drying device (manufactured by Okawara Seisakusho, product name: Ribocon, model: RM-50) as a vacuum agitation drying device, and heating was started from room temperature at 10 kPa to remove moisture under reduced pressure. The moisture content of the dried suspended particles was 1.4% when the internal temperature reached 90°C. The moisture content is defined as (100-X)%, where X% is the rate of weight change when the dried suspended particles are treated at a temperature of 135° C. for 1 hour.
The dried suspended particles were then semi-cured by heating. Curing conditions for semi-curing were 10 kPa and 110° C. temperature for 2 hours followed by a conical ribbon mixing/drying device.
Next, as a sieving step, the dried suspended particles were sieved using a wire mesh with an opening of 710 μm and a wire mesh with an opening of 250 μm. As a result, suspended particles that passed through a wire mesh with an opening of 710 μm but did not pass through a wire mesh with an opening of 250 μm were taken out from among the dried suspended particles.
The average particle size D50 of the resulting suspended particles (phenol resin particles 1) was measured using a laser diffraction particle size distribution analyzer (manufactured by HORIBA: LA-950V2) and found to be 560 μm.

(Preparation Example 2)
Phenol resin particles 2 were obtained in the same manner as in Preparation Example 1, except that the sequential addition temperature was set to 60° C., the reaction temperature was set to 60° C., and the suspended particles passed through a wire mesh having an opening of 330 μm were taken out in the sieving step. The average particle diameter D50 of the phenol resin particles 2 was 200 μm.

(Preparation Example 3)
Phenol resin particles 3 were obtained in the same manner as in Preparation Example 1, except that the sequential addition temperature was 75° C., the reaction temperature was 75° C., and the suspended particles that had passed through a wire mesh with an opening of 250 μm were taken out in the sieving step. The average particle size D50 of the phenol resin particles 3 was 100 μm.

(Preparation Example 4)
Phenolic resin particles 4 were obtained in the same manner as in Preparation Example 1, except that the sequential addition temperature was 95° C., the reaction temperature was 95° C., and the suspended particles that had passed through a wire mesh with an opening of 75 μm were taken out in the sieving step. The average particle size D50 of the phenol resin particles 4 was 20 μm.

(Preparation Example 5)
Phenol resin particles 5 were obtained in the same manner as in Preparation Example 1, except that the sequential addition temperature was set to 100° C., the reaction temperature was set to 100° C., and the suspended particles passed through a wire mesh having an opening of 63 μm were taken out in the sieving step. The average particle diameter D50 of the phenol resin particles 5 was 8 μm.

<Preparation of thermosetting resin composition>
(Examples 1 to 7, Comparative Example 1)
Each component was mixed so that it might become the formulation shown in Table 1, and the resin composition was manufactured. Specifically, the components shown in Table 1 were placed in a container, kneaded with a heating roll at about 90° C. for about 5 minutes, cooled and pulverized to obtain a thermosetting resin composition.
Details of the components shown in Table 1 are as follows.
(Phenolic resin)
Phenolic resin 1: novolac type phenolic resin (manufactured by Sumitomo Bakelite Co., Ltd., product name "SUMILITE RESIN PR-51470", weight average molecular weight: 3000)
・ Phenolic resin 2: Resol type phenolic resin (manufactured by Sumitomo Bakelite Co., Ltd., product name “Sumilite Resin PR-55329”)
(organic filler)
- Organic filler 1: Phenolic resin particles 1 obtained in Preparation Example 1
- Organic filler 2: Phenolic resin particles 2 obtained in Preparation Example 2
- Organic filler 3: Phenolic resin particles 3 obtained in Preparation Example 3
- Organic filler 4: Phenolic resin particles 4 obtained in Preparation Example 4
- Organic filler 5: Phenolic resin particles 5 obtained in Preparation Example 5
・Organic filler 6: Novolak type powdery phenolic resin (manufactured by Air Water Bellpearl Co., Ltd., product name “Bellpearl R100”, average particle size D50: 1.5 μm)
(Inorganic filler)
・ Inorganic filler 1: glass fiber (manufactured by Nitto Boseki, product name “CS3E479”)
(Additive)
・ Additive 1: Calcium hydroxide (manufactured by Kawai Lime Industry Co., Ltd., product name “Slaked lime super special”)
・ Additive 2: calcium stearate (manufactured by Nitto Kasei Kogyo Co., Ltd., product name “Ca-St”)
・Additive 3: Carbon black (manufactured by Mitsubishi Chemical Corporation, product name “#5”)

<Evaluation of physical properties of compact>
(Measurement of dimensional change rate)
The thermosetting resin composition obtained above is set in a mold coated with a release agent, compression molding is performed at 175 ° C. and a pressure of 30 MPa for 5 minutes, and a resin molded product with dimensions of 80 mm × 50 mm × (thickness) 5 mm got After that, post-curing was performed in an oven at 220° C. for 3 hours to obtain a molded body test piece.
This compact test piece was heat-treated by further standing at 120° C. for 250 hours. The thickness (t1) after this heat treatment was measured, and the dimensional change rate was obtained from the following formula (1).
Dimensional change rate (%) = [(t0-t1)/t0] x 100
The results are shown in Table 1 below.

(Measurement of specific gravity of resin molding)
Using the thermosetting resin composition obtained above, a test piece of a molded body of (diameter) 50 mm x (thickness) 3 mm was obtained by a transfer molding method under conditions of a temperature of 175°C, a transfer pressure of 50 MPa, and 5 minutes.
The specific gravity of this molded body test piece was determined in accordance with JIS K 6911 (general test method for thermosetting plastics). The unit of specific gravity (SP) is g/ ^cm3 .

The resin molded bodies of Examples were lighter in weight and had a reduced dimensional change rate than the resin molded bodies of Comparative Examples containing no organic filler.

Claims (6)

a thermosetting resin;
A thermosetting resin composition comprising an organic filler,
The specific gravity of the cured product of the thermosetting resin composition is 1.30 or more and 1.75 or less,
A thermosetting resin composition, wherein the dimensional change rate of a cured product of the thermosetting resin composition measured under the following conditions is 0.15% or less.
(Conditions) The thermosetting resin composition is molded at a mold temperature of 175° C., a curing time of 5 minutes, and a molding pressure of 30 MPa to obtain a molded body having dimensions of 80 mm×50 mm×5 mm (t0). After that, it is post-cured at 220° C. for 3 hours. The molded article after curing is allowed to stand at 120° C. for 250 hours, and the thickness (t1) after the treatment is measured. The dimensional change rate is obtained from the following formula (1).
Dimensional change rate (%) = [(t0-t1)/t0] x 100 2. The thermosetting resin composition according to claim 1, wherein the organic filler contains at least one selected from thermosetting resin cured products, heat-resistant thermoplastic polymer fine particles, and elastomers. The thermosetting resin composition according to claim 1 or 2, wherein the organic filler has an average particle size D50 of 0.1 µm or more and 600 µm or less. 4. The thermosetting resin composition according to any one of claims 1 to 3, wherein the organic filler is spherical, fragment-shaped, plate-shaped, scale-shaped, or needle-shaped. The thermosetting resin composition according to any one of claims 1 to 4, wherein the organic filler is 5% by volume or more and 50% by volume or less with respect to the entire thermosetting resin composition. The thermosetting resin composition according to any one of claims 1 to 5, further comprising an inorganic filler.