JP2006022130A - Thermoconductive resin composition and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition, excellent in thermoconductivity, also excellent in the total balance of dimensional stability, flowing property, etc., and capable of being used at a low cost for all purposes. <P>SOLUTION: This thermoconductive resin composition contains the following (a) to (e) components. (a) A crystalline resin having ≥200°C melting point, (b) A low melting alloy having its solidus temperature as lower than the melting point of the crystalline resin and its liquidus temperature as higher than the melting point by ≥100°C. (c) A metal or alloy powder having ≥400°C melting point or solidus temperature and good compatibility with the (b) component. (d) Inorganic powder having a poor compatibility with the (b) component and ≥20 W/mK thermoconductivity. And (e) a fibrous reinforcing material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat conductive resin composition. More specifically, the present invention relates to a heat conductive resin composition having both high thermal conductivity and dimensional accuracy of a molded product, and having an excellent balance between mechanical strength and fluidity, and a method for producing the composition.

Recent developments in electronics technology have made it possible to reduce the size of office automation equipment, and have promoted the transition from metal materials to resin materials. Along with the downsizing of devices, there is a strong demand for materials with high thermal conductivity as well as improved heat resistance against heat generation in the devices.
However, compared to metals, the resin itself has a low thermal conductivity, and there is no thermoplastic resin material that is excellent in thermal conductivity and heat resistance, moldability and material strength.

In order to impart thermal conductivity to the resin material, it is considered to add a filler having a high thermal conductivity.
Specifically, a composition comprising a thermoplastic resin having a thermal conductivity of 0.05 cal / cm · sec · ° C. or more and a metal / metal oxide powder having a specific particle size of 60% by weight or more is disclosed. (For example, refer to Patent Document 1).
However, the effect of improving the thermal conductivity is low with respect to the filling amount, and the maximum is about 2.8 cal / cm · sec · ° C. (about 1.1 W / mK), which is about 5 times that of the resin alone. Moreover, the compounding of an excessive filler brings about a rapid fluidity and a decrease in material strength, and cannot withstand practical use.

Moreover, the heat sink using the composition which used the metal oxide and the fiber reinforcement together is disclosed (for example, refer patent document 2).
However, the invention is limited to applications based on the technology of Patent Document 1, and the composition itself is not novel.

In addition, polyarylene sulfide (PAS) compositions in which specific carbon fibers (and graphite powder) having a high graphitization rate are blended to improve thermal conductivity are disclosed (for example, see Patent Documents 3 to 5). .)
However, the graphite powder is based on the same idea as in Patent Document 1, and excessive filling causes a decrease in fluidity and strength.
Addition of carbon fiber (CF) having a high graphitization rate compensates for this, and the efficiency of improving thermal conductivity is slightly higher depending on the fiber shape. However, in order to obtain a high thermal conductivity of 4 W / mK or more, it is necessary to increase the blending of CF with a high graphitization rate. As a result, the anisotropy of the molding shrinkage ratio increases and the molded product warps. It becomes easy to do.

As a technique for solving the disadvantages of the solid filler compounding system, for example, a low melting point metal that can be melted at the plasticizing temperature of the resin and a metal filler for dispersing the low melting point metal in the resin are added to the thermoplastic resin. A high thermal conductive resin composition is disclosed (for example, see Patent Documents 6 and 7).
However, in this method, even if the amount of the metal component is increased, the fluidity can be prevented from decreasing, but if the amount is increased to increase the thermal conductivity, the material density becomes extremely high, so the weight is reduced. The request was not satisfied. In addition, since the molten metal phase enclosing the solid metal filler is likely to aggregate, the appearance of the molded product may be deteriorated, and the molten metal forming the continuous phase may cause problems such as a decrease in heat resistance. .

Furthermore, a conductive resin composition to which a small amount of a carbon-based filler of 0.1 to 5.0 vol% is added is disclosed, and it is also disclosed that graphite / carbon fiber can be used (for example, see Patent Document 8).
However, since a small amount of carbon-based filler is basically added as a conductivity improving aid, there still remains a problem that the molten metal phase tends to aggregate and heat resistance is lowered due to high filling.

JP-A-5-86246 JP 2001-151905 A JP-A-2-163137 JP-A-9-157403 JP 2002-129015 A Japanese Patent Laid-Open No. 6-196684 JP 2002-3829 A JP 2002-212443 A

  The present invention has been made in view of the above-mentioned problems, has excellent thermal conductivity, and is excellent in overall balance of dimensional accuracy (precision moldability + heat stability), mechanical strength and fluidity, and at low cost. It aims at providing the resin composition which can be used universally.

In order to achieve the above object, as a result of intensive studies by the present inventors, a specific crystalline resin is blended with a metal powder in a solid state, an inorganic powder, and a low melting point alloy having specific melting characteristics. It has been found that by melt-kneading, the amount of the metal component (high melting point metal + low melting point metal) is small and the density is low, but very high thermal conductivity can be expressed.
That is, according to the present invention, the following heat conductive resin composition, a method for producing the heat conductive resin composition, and various molded articles are provided.
[1] A thermally conductive resin composition containing the following components (a) to (e) in the amounts shown in the following (i) to (v).
[component]
(A) Crystalline resin having a melting point of 200 ° C. or higher (b) Low melting point alloy whose solidus temperature is lower than the melting point of the crystalline resin and whose liquidus temperature is 100 ° C. or higher higher than the melting point (c) Alternatively, the metal or alloy powder having a solidus temperature of 400 ° C. or higher and good compatibility with the component (b) (d) The compatibility with the component (b) is poor and the thermal conductivity is 20 W / mK. Inorganic powder (e) fiber reinforcing material [blending amount]
(I) Crystalline resin (a): 40-60 vol%
(Ii) The inorganic powder (d): 10 to 30 vol%
(Iii) The fiber reinforcement (e): 10 to 25 vol%
(Iv) Volume ratio [(a) / [(b) + (c)]] of the crystalline resin (a) and the sum of the low melting point alloy (b) and the metal or alloy powder (c) : 2.0 to 30.0
(V) Volume ratio [(b) / (c)] of the low melting point alloy (b) and the metal or alloy powder (c): 1.0 to 4.0

[2] The component (b) is an alloy containing Sn as a main component and including at least one subcomponent selected from {Cu, Ni, Ag, Bi, Zn, Al, Mg}, and the component (c) The heat conductive resin composition according to [1], wherein is at least one metal or alloy selected from {Cu, Ni, Zn, Al, Fe}.
[3] The thermally conductive resin composition according to [1] or [2], wherein the component (d) is at least one component selected from {graphite, aluminum oxide, magnesium oxide, aluminum nitride, boron nitride}.

[4] The component (a) is a polyphenylene sulfide resin having a melt viscosity (300 ° C., 1200 sec ⁻¹ ) of 50 Pa · sec or less, the component (b) is mainly composed of Sn, {Cu, Ni, Ag , Bi, Zn} is an alloy containing at least one subcomponent selected from the group (c), and the component (c) is a powder of at least one metal or alloy selected from {Cu, Ni, Zn}, d) The thermally conductive resin composition according to [1], wherein the component is graphite and / or spherical alumina oxide.
[5] The thermally conductive resin composition according to [4], wherein the component (d) is graphite surface-treated with an epoxy resin and / or spherical alumina oxide surface-treated with an organosilane.
[6] The thermal conductivity of the thermal conductive resin composition is 4 W / mK or more, the bending breaking strength is 100 MPa or more, and the deflection temperature (low load) is 200 ° C. or more [1] to [5 ] The heat conductive resin composition in any one of.

[7] A method for producing a thermally conductive resin composition according to any one of [1] to [6], wherein the crystalline resin (a), the low-melting point alloy (b), the metal or alloy powder (C) The manufacturing method of the heat conductive resin composition including the process of melt-kneading the said inorganic powder (d) and the said fiber reinforcement (e) at the temperature which satisfy | fills the following conditions (1)-(3).
(1) Temperature at which the crystalline resin of component (a) is melted (2) Temperature above the solidus temperature of the low melting point alloy of component (b) (3) From the liquidus temperature of component (b) Temperature lower than 30 ℃

[8] A molded article comprising the thermally conductive resin composition according to any one of [1] to [6].
[9] A holding container for an optical pickup device comprising the heat conductive resin composition according to any one of [1] to [6].
[10] An optical pickup device including the holding container for an optical pickup device according to [9], a light source, a control IC for the light source, an objective lens, and a light receiving unit.
[11] An optical semiconductor holding container comprising the thermally conductive resin composition according to any one of [1] to [6].
[12] A semiconductor heat dissipation container comprising the thermally conductive resin composition according to any one of [1] to [6].
[13] A bearing comprising the thermally conductive resin composition according to any one of [1] to [6].

In the present invention, it is excellent in thermal conductivity, and has excellent overall balance of dimensional accuracy (precision moldability + heat resistance stability), mechanical strength and fluidity, and is economical and low cost. The heat conductive resin composition which can be performed, and the manufacturing method of this composition can be provided.
In addition, an optical pickup holding container made of this composition, an optical pickup device using this component, an optical semiconductor holding container, and a bearing can be provided.

Hereinafter, the heat conductive resin composition of this invention is demonstrated concretely.
The thermally conductive resin composition of the present invention includes the following components (a) to (e).
(A) Crystalline resin having a melting point of 200 ° C. or higher (b) Low melting point alloy (c) whose solidus temperature is lower than the melting point of the crystalline resin (a) and whose liquidus temperature is 100 ° C. higher than the melting point Metal or alloy powder having a melting point or a solidus temperature of 400 ° C. or higher and good compatibility with the component (b) (d) Incompatible with the component (b) and a thermal conductivity of 20 W / mK or higher Inorganic powder (e) Fiber reinforcement

The composition of the present invention can be produced by melt-kneading a mixture of the above components. When the components are melt-kneaded, the components (c) and (d) are uniformly dispersed in the component (a). The component (b) is dispersed in a semi-molten state while being entangled with the component (c) having good compatibility. When the melt-kneading is continued for a predetermined time, the component (b) is stretched and bonded to each other to form a network. This network is formed more finely due to the presence of the component (d). Further, due to the presence of the component (d), reaggregation of the component (b) can be prevented. As a result, since the heat conduction path can be formed efficiently, high heat conductivity can be obtained even with a small amount of metal. In addition, when the composition is subjected to secondary molding such as injection molding, it is possible to suppress bleeding out of the component (b) on the surface of the molded product, so that the appearance of the molded product is improved. Moreover, since it can be combined with a fiber reinforcement, the mechanical heat resistance such as the deflection temperature under load can be improved.
Hereinafter, each component will be described.

(A) Crystalline resin There is no particular limitation as long as it is a crystalline resin having a melting point of 200 ° C. or higher and fluidity that can be blended with other components. A resin having a melting point of less than 200 ° C. is generally unsuitable because it has a glass transition temperature (softening temperature) of room temperature or lower, and thus lacks dimensional accuracy and thermal dimensional stability even when the composition of the present invention is used. The melting point is preferably 230 ° C. to 400 ° C., more preferably 250 ° C. to 350 ° C.
The melting point is the peak temperature of the melting endotherm when measured with a differential scanning calorimeter (DSC) at a sample amount of about 10 mg and a scanning rate of 20 ° C./min.

As such a crystalline resin, polyamide represented by polyamide 6 (PA-6), polyethylene terephthalate (PET), polyester represented by polycyclohexylene terephthalate (PCT), syndiotactic styrene (SPS), Examples thereof include polyarylene sulfide (PAS) typified by polyphenylene sulfide (PPS), polyketone resin typified by polyether ether ketone (PEEK), and the like.
Among these, PPS is preferable because it is excellent in flame retardancy, chemical resistance, and water resistance, is not decomposed by other components used in the present invention, and has high strength for fluidity. Among PPS, PPS having a melt viscosity of 50 Pa · sec or less is preferable, and PPS of 20 Pa · sec or less is particularly preferable.
The melt viscosity means a value measured with a capillary rheometer under conditions of a temperature of 300 ° C. and a shear rate of 1200 sec ⁻¹ .

(B) Low melting point alloy (b) A component forms the metal network which included (c) component in the said (a) component. Thereby, the thermal conductivity of the resin composition is improved.
In the present invention, a low melting point alloy having a solidus temperature lower than the melting point of the crystalline resin (a) and a liquidus temperature higher by 100 ° C. or more than the melting point of the resin is used. Since the resin composition of the present invention forms a network of the component (b), the temperature between the solidus temperature and the liquidus temperature of the component (b), that is, the temperature at which the component (b) is in a semi-molten state. Therefore, it is preferable to prepare by kneading stably. When the difference between the melting point of the component (a) and the liquidus temperature of the component (b) is less than 100 ° C., there is a risk of lack of stability in realistic production.
The solidus temperature and the liquidus temperature are values measured by the following method.
The alloys of each composition are completely melted and the melt is cooled very slowly. The temperature change in the cooling process is measured with a thermocouple, and a thermal analysis curve is created. The transformation point is read from the thermal analysis curve to obtain the solidus temperature and the liquidus temperature.

The low melting point alloy may be appropriately selected according to the melting point of the component (a) and satisfying the above conditions. However, in consideration of toxicity, a lead-free solder type alloy is preferable.
As a specific alloy, for example, an alloy containing Sn as a main component and at least one of subcomponents represented by {Cu, Ni, Ag, Bi, Zn, Al, Mg} is preferable. In particular, an alloy formed by blending at least one of {Cu, Ni, Ag, Bi, Zn} with Sn as a main component because of its familiarity (compatibility, wetting) with the component (c) described below. Is preferred.

  For example, when polyphenylene sulfide having a melting point of 280 ° C. is used as the component (a), preferable examples of the component (b) include Sn—Cu and Sn—Ag—Cu alloys.

(C) Metal or alloy powder The (c) component, together with the (b) component, forms a metal network inside the (a) component and improves the thermal conductivity of the resin composition. In addition, since the component (b) is completely phase-separated from the component (a), it bleeds out from the resin composition, but can be suppressed by adding the component (c).
In the present invention, the component (c) uses a metal or alloy powder having a melting point or a solidus temperature of 400 ° C. or higher and good compatibility with the component (b). The component (c) needs to be in a solid state in the production process of the resin composition, and in combination with the component (b), the component (b) has good compatibility in the molten state, and the component (b) This is because it must be easily dispersible in the melt.
Here, “the compatibility with the component (b) is good” means that the component (b) and the component (c) are mixed at a temperature equal to or higher than the solidus temperature of the component (b) ( It means that the component c) has the property of being dispersed in the molten phase of the component (b).

If the melting point or the solidus temperature is less than 400 ° C., it is not suitable because it softens due to the resin temperature during kneading and tends to be deformed, and it becomes difficult for the low melting point alloy to form a network due to the change in surface area. The melting point or solidus temperature is preferably 500 ° C. or higher, more preferably 1000 ° C. or higher.
Specific examples of the metal or alloy powder include metal powder selected from {Cu, Ni, Zn, Al, Fe} or the like, or an alloy powder containing at least one of them as a main component. Preferably, it is a metal powder selected from {Cu, Ni, Zn}, or an alloy powder containing at least one of them as a main component.
Although the particle size of these powders is not limited, the average particle size is preferably about 10 to 50 μm in consideration of the blending effect and the risk during molding.
There are no limitations on the method for producing the metal or alloy powder, but from the viewpoints of purity and specific surface area, a dendritic powder produced by the electrolytic method and a foil piece shaped powder produced by the stamp method are preferred.

(D) Inorganic powder The component (d) serves as a dispersion aid for the component (c) and prevents the component (b) from precipitating on the surface of the molded product to cause poor appearance. Moreover, as a heat conductivity improving material, it works complementarily with the above-mentioned components (b) and (c) which are metals, and adjusts the balance between the thermal conductivity, the appearance of the molded product, and the strength. This can reduce the weight of the resin composition.
As the component (d), those having poor compatibility with the component (b) and having a thermal conductivity of 20 W / mK or more are used. If the compatibility with the component (b) is good, the component (d) and the component (c) are likely to aggregate via the component (b), which is inappropriate because it causes poor appearance.
Here, “(b) component is poorly compatible” means that component (d) is mixed with component (b) and component (d) at a temperature equal to or higher than the solidus temperature of component (b). Does not easily disperse in the melt phase of component (b), but rather has the property that component (b) aggregates alone.
Moreover, if thermal conductivity is less than 20 W / mK, the improvement rate of the thermal conductivity of a resin composition will become small. The thermal conductivity is preferably 30 W / mK or more, and particularly preferably 50 W / mK or more.

Specific examples of the inorganic powder include powders of graphite, aluminum oxide, magnesium oxide, aluminum nitride, boron nitride and the like. Among these, graphite and spherical aluminum oxide powder are particularly preferable.
The component (d) is preferably one that is easily dispersed in the component (a), and therefore, one that has been surface-treated with a compatibilizer is preferable. As a result, the environmental stability and strength of the resin composition and the molded body comprising the resin composition can be improved, and damage to the molding machine can be reduced when the resin composition is processed.
As the inorganic powder surface-treated with a compatibilizing agent, for example, graphite pre-treated with an epoxy resin, spherical aluminum oxide pre-treated with an organic silane, or the like is preferable.
The particle size of the inorganic powder is not particularly limited, but the same particle size as the component (c) is preferable.

(E) Fiber reinforcement (e) A component is added in order to provide the material strength required for a final product. A commonly used fibrous filler can be used for this component. Examples thereof include glass fiber (GF), whisker, and carbon fiber (CF).
The glass fiber may be a chopped fiber or a milled fiber that has been shortened into powder in advance.
Whisker is a crystalline fiber, and typical examples include potassium titanate whisker, calcium metasilicate whisker, and aluminum borate whisker.
As the carbon fiber, either PAN type or pitch type can be used.
Of these, glass fibers and whiskers are preferable, and glass fibers are particularly preferable in consideration of the versatility of the composition in terms of raw material costs.

Further, the fibrous filler may be previously treated with a known surface treatment agent (silane-based, titanate-based, epoxy resin, etc.).
The type and grade of the fibrous filler can be selected depending on the reinforcing effect and application. In general, a fiber having a short fiber length has little reinforcing effect, but often has a sufficient effect for preventing microcracks, and can be prevented from warping of a molded product because it is reinforced relatively isotropically.
Depending on the required characteristics, two or more types may be blended and used. For example, a combination of a relatively small amount of whisker and chopped GF can be mentioned.

The heat conductive resin composition of this invention can be manufactured by melt-kneading what mixed said (a)-(e) component.
Melt kneading can be carried out by various known methods. For example, as the most general method, the above components (a) to (d) are dry blended in advance using a Henschel mixer, super mixer, tumbler or the like, and then supplied to a single-screw or twin-screw kneading extruder, etc. Furthermore, there is a method of obtaining pellets of the heat conductive resin composition by supplying the component (e) from the middle of the extruder, melt kneading, and then granulating.

  When kneading each of the above components, in order to efficiently form a low melting point alloy network inside the resin composition, the material temperature during kneading is the temperature at which the crystalline resin of component (a) is melted, and the low melting point The temperature is preferably between the solidus temperature and the liquidus temperature of the alloy. Under this temperature condition, the low melting point alloy as the component (b) has fluidity, but microscopically takes a phase separation structure and exhibits structural viscosity. By kneading in this state, the component (b) is included in the component (c) having good compatibility while being deformed and dispersed. When further kneaded, the low melting point alloy is fused while being stretched using the encapsulated component (c) as a core to form a three-dimensional network structure. Since this structure is easily held by the structural viscosity of the low melting point metal, it is efficiently formed inside the resin composition. By this network, high thermal conductivity can be imparted to the resin composition.

In addition, since a strong shearing force is applied to the input material during kneading, the composition temperature during kneading rises above the set temperature of the kneader. Therefore, it is preferable to set the temperature at the time of kneading so that it is sufficiently lower than the liquidus temperature of the low melting point alloy. Specifically, it is preferable to set so that the composition can be kneaded at a temperature lower by 30 ° C. or more than the liquidus temperature of the low melting point alloy.
From the above viewpoint, the temperature during melt-kneading is preferably controlled so as to satisfy the following conditions.
(1) Temperature at which the crystalline resin of component (a) is melted (2) Temperature above the solidus temperature of the low melting point alloy of component (b) (3) 30 ° C. or more from the liquidus temperature of component (b) Low temperature

  In the resin composition of the present invention, the proportion of the component (a) in the composition is 40 to 60 vol%. When (a) is less than 40 vol%, the fluidity of the final composition is remarkably deteriorated and the versatility is inferior from the viewpoint of moldability. On the other hand, if it exceeds 60 vol%, it is difficult to form a network of the low melting point alloy as the component (b), and the thermal conductivity is greatly reduced. Preferably, it is 45-55 vol%, More preferably, it is 47-53 vol%.

In the thermally conductive resin composition of the present invention, the volume ratio [(a) / [(b) + (c)]] of the component (a) and the components (b) and (c) is 2.0 to 30.0. This value means the volume ratio of the total amount of metal components to the amount of resin in the composition. When this value is less than 2.0, the amount of metal is too large. For this reason, when the ratio of the component (b) and the component (c) described below is small, the fluidity is lowered and the moldability is inferior. When the ratio is large, the component (b) is deposited on the surface and the appearance is poor. cause.
On the other hand, when this value exceeds 30.0, the amount of metal is too small to form a low melting point alloy network, and the thermal conductivity of the composition cannot be improved. A preferable range is 2.5 to 10.0, and more preferably 3.0 to 7.0.

Moreover, the volume ratio [(b) / (c)] of (b) component and (c) component is 1.0-4.0. This indicates the capacity ratio between the low melting point alloy and the high melting point metal. When this value is less than 1.0, it becomes difficult to form a network of a low melting point alloy, and only a thermal conductivity comparable to that obtained when simply filling with a metal filler is obtained. On the other hand, when this value exceeds 4.0, there are too many low melting point alloys, the dispersion | distribution in resin which is (a) component deteriorates, and an external appearance defect generate | occur | produces, and it becomes difficult to form metal network itself. The preferred range is 1.3 to 3.0, more preferably 1.5 to 3.0.
2.7.

  The proportion of the component (d) in the composition is 10 to 30 vol%. If it is less than 10 vol%, it is necessary to increase the total amount of metal in order to increase the thermal conductivity. As a result, the precipitation of the component (b) on the surface of the molded article increases, resulting in poor appearance. On the other hand, when this value exceeds 30 vol%, the fluidity of the composition is remarkably deteriorated, and the network formation of the low melting point alloy is hindered, so the thermal conductivity is lowered. A preferred range is 15 to 27 vol%, particularly preferably 15 to 25 vol%.

The proportion of the component (e) in the composition is 10 to 25 vol%. If this value is less than 10 vol%, not only the occurrence of cracks in the molded product cannot be prevented, but also the deflection temperature under load is lowered, which may not be used for heat resistance. On the other hand, if it exceeds 25 vol%, the network formation of the low melting point alloy is hindered, which hinders the improvement of the thermal conductivity. A preferable range is 10 to 20 vol%, and a more preferable range is 13 to 20 vol%.
Since the component (e) often acts in the direction of inhibiting the network formation of the low melting point metal, it is preferable to add as little as possible. However, if the amount of fiber reinforcement is too small, cracks often occur during cooling after molding due to the difference in thermal shrinkage between the resin and other fillers. In order to maintain a series of these balances, it is preferable to add the fiber reinforcement within a certain blending range.

In addition to the essential components (a) to (e), known components can be added as long as the effects of the present invention are not impaired.
For example, a pigment such as carbon black can be added. In this case, the addition amount is preferably 1% by weight or less with respect to the entire composition.
In addition, in order to compensate for the drawbacks of the crystalline resin as component (a), other resins may be added. For example, when PPS is a base, polysulfone or polyphenylene ether can be blended in order to suppress generation of molding burrs and warpage of molded products. In addition, polytetrafluoroethylene (PTFE), ultrahigh molecular weight polyethylene, or the like can be blended to improve slidability for bearings and the like. The blending amount is preferably within 20 vol% of the total resin blended in the composition.
Furthermore, an antistatic agent such as ketjen black can be added. In this case, the addition amount is preferably 1% by weight or less with respect to the entire composition.

In the heat conductive resin composition of this invention, the heat conductivity can be 4 W / mK or more. A resin composition having a thermal conductivity of less than 3 W / mK can be designed as a relatively balanced material even in the range of the prior art, but it is difficult to do so. If the thermal conductivity is 4 W / mK or more, it can be determined that the heat dissipation of the molded product is good, and the application range of the resin composition is widened. The thermal conductivity is preferably 5 W / mK or more, more preferably 7 W / mK or more.
Moreover, it is preferable that bending fracture strength is 100 Mpa or more. If it is 100 MPa or more, it is within the range of the strength of a precision molding material for a structural member that is generally used, and can be easily applied to various applications. The bending breaking strength is more preferably 120 MPa or more, and particularly preferably 150 MPa or more.
Further, the deflection temperature under load (low load) is preferably 200 ° C. or higher. When the temperature is 200 ° C. or higher, the heat resistant dimensional stability is sufficient when the resin composition of the present invention is applied to an optical pickup, a holding container for an optical semiconductor, and the like, which are main uses. More preferably, it is 220 ° C. or higher, and particularly preferably 250 ° C. or higher.
The deflection temperature under load is a value measured with a load of 0.46 MPa in accordance with ASTM D648.

The heat conductive resin composition of the present invention has excellent heat conductivity, mechanical properties, and heat resistance (dimensional stability) while retaining the characteristics of a resin that is easy to mold and lightweight. Therefore, it can be suitably used as a material for parts that need to release heat generated inside the device to the outside. For example, it can be suitably used for various components such as a holding container for an optical pickup device, a holding container for an optical semiconductor, and a semiconductor heat dissipation container.
Hereinafter, as an example to which the thermally conductive resin composition of the present invention is applied, a holding container for an optical pickup device and an optical (study) pickup device using the same will be described.
The optical pickup device is an audio CD (compact disc), CD-ROM, DVD (digital video disc), DVD-ROM, CD-R / RW, DVD ± R / RW, DVD-RAM, etc. Is a general term for drive devices that read and write information in a physically non-contact manner with these recording media using a laser beam.
The present invention is not limited to the optical pickup device holding container and the optical pickup device shown below.

FIG. 1 is a schematic view showing an example of the structure of an optical pickup device, and FIG. 2 is a perspective view of a holding container for the optical pickup device mounted on the optical pickup device.
The optical pickup device 1 includes a chassis 10, a main shaft 11 and a sub shaft 12 that are attached to the chassis 10, and an optical pickup 13 that is slidably attached to the main shaft 11 and the sub shaft 12.

The optical pickup 13 (also referred to as an OP base) is the heart of the device, and holds a semiconductor laser, a half mirror, an objective lens, a collimator lens, and a photodiode (light receiving unit) as light sources for the optical pickup device. It is a module that is mounted inside the container 13a and integrated in a compact manner.
The optical pickup device holding container 13a plays a role as an instruction stand for supporting and fixing the whole of the above components, and is integrally formed with the base body 21 and the base body 21 arranged at one end of the base body 21 at a predetermined interval. While having two main bearings 22, 22 ′ formed, the other end of the base 21 has a sub-bearing 23 formed integrally with the base 21. The main bearings 22, 22 ′ and the auxiliary bearing 23 are loosely inserted into the main shaft 11 and the auxiliary shaft 12, respectively. The semiconductor laser is attached to the laser diode holder attachment portion 24.

Next, the operation of the optical pickup device 1 will be described.
The optical pickup 13 is moved in the radial direction of the optical disk 14 along the main shaft 11 and the sub shaft 12 by the driving force of a driving motor (not shown) controlled by a control system (not shown) to record information. Perform playback.
In the optical pickup 13, the light emitted from the semiconductor laser is reflected by an optical component (not shown) such as a half mirror so as to be perpendicular to the optical disk 14, and is directed from the emission port 25 formed in the base 21 toward the optical disk 14. Are emitted. Then, the reflected light from the optical disk 14 passes through the optical component and enters a light receiving unit (not shown). The data signal recorded on the optical disk 14 is read from the received light.

In an optical pickup device, the positional accuracy and stability of a laser beam are most strictly required. The position of the beam fluctuates due to the dimensional variation of the OP base. In the case of the OP base made of PPS resin, the optical axis shift due to the temperature change is the largest factor.
Since the semiconductor laser generates heat, the temperature at the mounting portion is partially increased, and the deformation of the OP base is increased in addition to the influence of the environmental temperature. Moreover, since the temperature of the semiconductor laser mounting portion rises, there is a problem that the life of the semiconductor laser is shortened.

In recent years, the use of rewritable optical disk devices such as CD-R / RW devices has increased, and the amount of laser heat generated during writing has become significantly larger than that of read-only devices. For this reason, from the viewpoint of heat dissipation performance, it has been considered difficult to resinize the OP base.
In addition, in a read-only machine such as a DVD-ROM, there is a concern about optical axis misalignment due to heat retention due to the thinning of the OP base accompanying the downsizing of the optical pickup. The demand for high thermal conductivity is increasing.

As a result of the simulation using the actual OP base shape and the basic characteristics of the semiconductor laser, the present inventors have found that the thermal conductivity is 4 W / mK or more when the thermal contact between the semiconductor laser and the OP base is good. Results that there is a sufficient heat dissipation effect. In addition, when the performance required for the OP base, such as thermal conductivity, was evaluated in an actual molded product, the thermal conductivity was 4 W / mK or more. From the viewpoint of moldability, the fluidity of the composition was the spiral flow length. It has been confirmed that the bending fracture strength should be 90 MPa or more.
The thermally conductive resin composition of the present invention satisfies this requirement, and can be said to be a composition suitable for parts that require severe heat dissipation and dimensional stability.

Hereinafter, the present invention will be described more specifically with reference to examples.
Example 1
The following raw materials were used as the components (a) to (e), which are constituent materials of the composition. In addition, (a)-(d) component is a powder raw material.
(A) Component: Polyphenylene sulfide (PPS, manufactured by DIC Corporation, H-1: melting point 280 ° C.) The melt viscosity at 300 ° C. and a shear rate of 1200 sec ⁻¹ is 15 Pa · sec.
(B) Component: A kind of lead-free alloy, Sn-Cu alloy atomized powder (manufactured by Senju Metal Industry Co., Ltd., solidus temperature 230 ° C., liquidus temperature 430 ° C., average particle size 25 μm)
(C) Component: Electrolytic (dendritic) copper powder (Mitsui Metal Mining Co., Ltd., MD-1: average particle size 35 μm, solidus temperature (melting point) 1080 ° C.)
(D) Component: Graphite powder (manufactured by Nippon Graphite Industries Co., Ltd., PAG-5: Artificial graphite powder, thermal conductivity 150 W / mK, average particle size 40 μm)
(E) Component: Chopped glass fiber (Asahi Fiber Glass Co., Ltd., fiber length 3 mm chop, fiber diameter 10 μm)

[Preparation of composition]
Weigh out a predetermined amount so that the component (a) is 50 vol%, the component (b) is 10 vol%, the component (c) is 5 vol%, and the component (d) is 20 vol%, and put into a super floater mixer (manufactured by Kawata). And premixed for 3 minutes.
This is a biaxial kneading in which the barrel set temperature near the material charging part is set to 280 ° C., the set temperature is gradually increased toward the die side, and the set temperature on the die side (near the tip of the extruder) is set to 320 ° C. While feeding to an extruder (Toshiba Machine Co., Ltd., TEM37BS), from the middle, component (e) GF, which is the component, is side-feeded so that the volume ratio in the composition is 15 vol%, and melt-kneaded and extruded. A pellet-shaped resin composition was obtained.
The resin composition was evaluated for thermal conductivity, material strength, fluidity, and molded product appearance. In addition, the resin temperature in the extruder was measured in order to optimize the temperature conditions during injection molding and to evaluate the heat generation due to shear during kneading.
The evaluation method is as follows.

(1) Resin temperature at the time of compounding The resin temperature in the die block at a point about 5 cm away from the screw tip of the twin-screw kneading extruder used at the time of kneading the composition was measured. This temperature represents the actual resin temperature during kneading.
(2) Thermal conductivity The pellet-shaped resin composition was press-molded at 320 ° C. to produce a 5 mm-thick flat plate, which was used as a sample molded body.
The thermal conductivity was measured using a steady heat flow meter (manufactured by DYNATEC R & D, model number TCHM-DV). In order to accurately measure the temperature difference between the upper and lower surfaces of the sample, as shown in FIG. It was embedded by hot press. By using the hot press, the flatness of the upper and lower surfaces of the sample molded body 31 is also improved. In order to stabilize the heat flow, it was measured after heating to a predetermined temperature for 1 hour.

(3) Spiral flow length (SFL)
A spiral flow mold having a thickness of 1 mm was used, and the flow length when injection molding was performed at a mold temperature of 135 ° C., a resin temperature of 320 ° C., and an injection pressure of about 100 MPa (1000 kgf / cm ² ) was evaluated. In general, when the SFL is less than 50 mm, molding becomes extremely difficult.
(4) Bending Fracture Strength ASTM standard bending test pieces were molded under the same temperature conditions as the above SFL, and evaluated according to ASTM D-790. The shape of the test piece was length × width × thickness = 127 × 12.7 × 3.2 mm.
(5) Appearance of injection molded product The surface appearance of the bending test piece of (4) above was visually evaluated. Evaluation was made according to four ranks of excellent / good / good / × (impossible) depending on the roughness of the surface and the degree of flow mark. Further, the microscopic appearance was evaluated by observing the surface of a part of the composition with an optical microscope.
Table 1 shows the evaluation results of Example 1 and Example 2-7 described later.

  Example 1 shows a case where the blending amount of each raw material is approximately in the middle of the limited range of the component ratio and has a suitable composition. As a result of the evaluation, the thermal conductivity, bending breaking strength and fluidity were all high. As for the appearance, as a result of observation with a microscope (magnification 100 times), it was observed that fine particles of component (b) were bleeding out uniformly on the surface of the molded product. However, it was judged by visual observation that there was a homogeneous appearance and there was no practical problem.

Example 2-6
A resin composition was produced and evaluated in the same manner as in Example 1 except that the blending ratio of the components (a) to (e) was changed as shown in Table 1.
Example 2 shows an example in which the amount of component (a) is reduced to the lower limit and (b) / (c) is increased to the limit. Although it was prepared in the direction of increasing the fluidity by increasing (b), the resin temperature rise during kneading was large, and the fluidity of SFL was close to the lower limit for molding. However, the thermal conductivity was the highest. As for the appearance of the molded product, a flow mark was observed on the surface of the molded product, but this was practically acceptable.

Example 3 shows an example in which the blending amount of the component (a) is increased to the upper limit and (b) / (c) is decreased to the lower limit. As a result, the thermal conductivity was 5 W / mK and the fluidity was excellent. As a result of reducing the blending amount of GF to the lower limit, the bending rupture strength was slightly low but practically no problem. The appearance of the molded product was extremely good, comparable to general filler grades.
Example 4 shows an example in which the ratio (a) / {(b) + (c)} of the total metal amount to the component (a) is increased. As a result of balancing by increasing the component (d) to the upper limit, it was confirmed that the heat conductivity was maintained at a high level while the strength and fluidity were high. The appearance of the molded product was also very good.

  Example 5 shows an example in which the fiber reinforcing material of the component (e) is added up to the upper limit with emphasis on strength. As a result, the resin temperature at the time of kneading was high, and the fluidity of SFL was also the lower limit for practical use. When the amount of the component (e) increases, it becomes difficult to form a network of the component (b), so that the thermal conductivity also decreases. Since the fluidity was low, a flow mark was seen on the surface of the molded product. However, in general, it was practically acceptable.

  Example 6 shows an example in which the ratio (a) / {(b) + (c)} of the total amount of metal to the component (a) is increased to the upper limit. Moreover, the fiber reinforcing material of (e) component was also added to the upper limit. As a result, the level of bending fracture strength was extremely high and the fluidity was excellent. The appearance of the molded product was extremely good, comparable to general filler grades.

Example 7
As the component (e), chopped carbon fiber (Mitsubishi Chemical Co., Ltd., K223HG, fiber diameter 10 μm, fiber length 6 mm) was used, and the mixing ratio of components (a) to (e) was changed as shown in Table 1. In the same manner as in Example 1, a resin composition was produced and evaluated.

Comparative Example 1-6
A resin composition was produced and evaluated in the same manner as in Example 1 except that the blending ratio of the components (a) to (e) was changed as shown in Table 2.
The evaluation results of Comparative Example 1-6 are shown in Table 2.

Comparative Example 1 is an example without component (c). Without the Cu powder as the component (c), the Sn-Cu alloy as the component (b) is not compatible with the PPS resin and thus completely separates and bleeds out to the surface of the extruder strand. . Similarly, a large spot of Sn—Cu alloy was generated on the surface of the injection molded product. Although the composition was obtained by changing all the metal components of Example 1 to Sn—Cu alloy, the fluidity and strength were also lowered because the dispersibility of the Sn—Cu alloy was extremely low.
In addition, it was confirmed that the same situation was observed when the component (b) was 12.5 vol% and the component (c) was 2.5 vol% [(b) / (c) = 5].

Comparative Example 2 is an example without component (b). Since a network of Sn—Cu alloy cannot be formed, this corresponds to the case of Example 1 in which a heat conductive solid filler is simply blended. As a result, fluidity and thermal conductivity were greatly reduced.
In addition, as a result of examining the case where the component (b) is 5.0 vol% and the component (c) is 10.0 vol% [(b) / (c) = 0.5], the fluidity is slightly improved. The thermal conductivity was confirmed to be as low as about 3.0 W / mK.

Comparative Example 3 is an example in which the total amount of metal {(b) + (c)} relative to the resin is increased by reducing the component (d). Since (b) / (c) is in the proper range, the thermal conductivity, fluidity and bending rupture strength show good values, but there is little graphite (d) having the effect of finely dispersing the metal network. For this reason, metal spots that can be visually observed on the surface of the molded product were observed. In addition, Sn—Cu alloy lumps were also observed in the strands during kneading.
In contrast to Comparative Example 3, Comparative Example 4 is an example in which (b) / (c) is increased in order to increase fluidity by increasing the component (d). Although the component (e) was also low, the viscosity was high and the temperature of the resin during kneading increased to about 400 ° C., resulting in a lot of fuming accompanying decomposition of the PPS resin. Although the thermal conductivity was good, the more difficult the injection molding, the lower the fluidity and the lower the bending rupture strength.

The comparative example 5 shows the example which increased the fiber reinforcement which is (e) component. As a result, the increase in viscosity due to GF was very large, and the resin temperature during kneading exceeded 400 ° C. Therefore, it was dangerous to prepare the material.
Comparative Example 6 is an example in which the amount of the fiber reinforcing material as the component (e) is reduced and the other composition ratios are close to the optimum composition. It was found that the fluidity was particularly good and the thermal conductivity and the appearance of the molded product were good, but the material strength was low and it could not withstand practical use with an actual molded product.

Example 8
The component (b) was Sn-Ag-Cu alloy having a composition of Sn-2.0Ag-6.0Cu (manufactured by Senju Metal Industry Co., Ltd., M33: solidus temperature 217 ° C, liquidus temperature 380 ° C, A resin composition was produced and evaluated in the same manner as in Example 1 except that the average particle size was 40 μm.
The evaluation results of Examples 8-10 and Comparative Example 7 are shown in Table 3.

  As a result of Example 8, the resin temperature at the time of kneading was lower by 30 ° C. or more than the liquidus temperature, and the material characteristics equivalent to Example 1 were obtained.

Example 9
A resin composition was produced and evaluated in the same manner as in Example 8 except that the setting temperature of the extruder when producing pellets of the resin composition was 350 ° C.
This is an example in which the extruder temperature at the time of kneading was set to 350 ° C., and as a result, the resin temperature was increased to 370 ° C., and the fluidity and material strength were almost the same as in Example 8, but the thermal conductivity decreased. It was confirmed that it became a trend.

Example 10
(D) A resin composition was produced in the same manner as in Example 1, except that the component was spherical alumina (manufactured by Micron Corporation, AX35-125: thermal conductivity 25 W / mK, average particle size 35 μm). evaluated.
Compared with Example 1, the thermal conductivity of the component (d) is low (the thermal conductivity of graphite is usually about 50 to 100 W / mK), and the features of the present invention are exhibited. Was confirmed. When changed to spherical alumina, the fluidity was improved and the appearance of the molded product was further improved. Although the thermal conductivity was lowered, it was confirmed that it still maintained a high level.

Comparative Example 7
(D) A resin composition was produced in the same manner as in Example 1 except that the components were glass beads (manufactured by Potters Ballotini Co., Ltd., GB731: thermal conductivity 1 W / mK, average particle size 30 μm). ,evaluated.
This example shows the effect when the component (d) is considered only as a dispersion aid for the components (b) + (c). Although the dispersibility of the Sn—Cu alloy and the surface appearance of the molded product were judged to be good, the thermal conductivity was greatly reduced. As a result, it was confirmed that the thermal conductivity of the component (d) also contributed to the thermal conductivity of the composition.

Example 11
Using the thermally conductive resin composition produced in Example 1, an OP base for DVD-ROM having the shape shown in FIG. 2 was molded. The molding temperature conditions were a resin temperature of 330 ° C. and a mold temperature of 145 ° C.
The OP base is approximately 25 mm long, 40 mm deep, 13 mm high, and 2.0 mm thick.
This OP-based heat dissipation was evaluated by the following method.
A semiconductor laser as a light source was mounted on the OP base, and the temperature rise of the semiconductor laser holder (distance from the laser surface of about 3 mm) was measured with a thermocouple.
With the semiconductor laser emitted, the OP base was set in a constant temperature bath at an ambient temperature of 60 ° C., and the temperature when the thermal equilibrium was reached was measured. As a result, the temperature rise of the measurement part was stopped at 2.5 ° C., and a sufficient heat dissipation effect was recognized.

  In addition, the feature that the burr | flash which generate | occur | produces in the molded article using this material is very few was also confirmed. This is because of the high thermal conductivity, the fluid component (resin + metal) flowing into the parting surface of the mold rapidly solidifies, and it is assumed that the burrs are reduced. It can be said that there is.

Comparative Example 8
Except using polyphenylene sulfide (made by Idemitsu Petrochemical Co., Ltd., K531A1: thermal conductivity 0.5 W / mK, SFL 80 mm), which is a general OP-based grade for DVD-ROM, the same as Example 11 An OP base for DVD-ROM was molded and evaluated.
As a result, a temperature increase of + 8 ° C. was observed in the evaluation of heat dissipation.

Comparative Example 9
An aluminum die-cast OP base having the same shape was produced, and the heat dissipation was evaluated in the same manner as in Example 11.
As a result, a temperature increase of + 1 ° C. was observed.

  Incidentally, the optical axis deviation amount at 20 ° C. → 80 ° C. was measured using the OP base produced in Example 11 and Comparative Examples 8 and 9, but Example 11 has almost the same optical axis deviation as Comparative Example 8. It was also confirmed that it has sufficient temperature characteristics as an OP base.

The thermally conductive resin composition of the present invention is excellent in thermal conductivity (heat dissipation), dimensional stability, fluidity and strength, and a molded product obtained by processing this has a good surface appearance.
Further, by using the resin composition of the present invention, it is possible to provide an optical pickup device holding container excellent in dimensional stability and heat dissipation, and an optical pickup device including the component.
The resin composition of the present invention can be suitably used as other optical semiconductor holding containers that generate heat, and general semiconductor heat dissipation containers as well as semiconductor lasers for optical pickups.

  In addition, a resin composition containing a filler with a small friction coefficient is generally used for sliding members such as bearings. However, in a member that slides at high speed, heat generated on the friction surface is retained on the surface. The base material may be softened, the filler may be peeled off from the surface, and so-called abrasive wear may progress. The material of the present invention can also be suitably used for this application. For example, when graphite and CF which express a low friction coefficient are blended and a soft filler is blended, the sliding counterpart material is rarely damaged. In addition, the temperature rise due to heat generation and heat retention can be further reduced by changing a part of PPS as an optional component to PTFE.

It is a schematic diagram which shows the example of the structure of an optical pick-up apparatus. It is a perspective view of the holding container for optical pickup devices mounted on the optical pickup device. It is the schematic for demonstrating the measuring method of thermal conductivity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical pick-up apparatus 10 Chassis 11 Main axis | shaft 12 Sub axis | shaft 13 Optical pick-up 13a Holding container for optical pick-up apparatuses 14 Optical disk 21 Base | substrate 22, 22 'Main bearing 23 Sub bearing 24 Laser diode holder attachment part 25 Outlet

Claims (13)

The heat conductive resin composition which contains the following (a)-(e) component and the compounding quantity shown to the following (i)-(v).
[component]
(A) Crystalline resin having a melting point of 200 ° C. or higher (b) Low melting point alloy whose solidus temperature is lower than the melting point of the crystalline resin and whose liquidus temperature is 100 ° C. or higher higher than the melting point (c) Alternatively, the metal or alloy powder having a solidus temperature of 400 ° C. or higher and good compatibility with the component (b) (d) The compatibility with the component (b) is poor and the thermal conductivity is 20 W / mK. Inorganic powder (e) fiber reinforcing material [blending amount]
(I) Crystalline resin (a): 40-60 vol%
(Ii) The inorganic powder (d): 10 to 30 vol%
(Iii) The fiber reinforcement (e): 10 to 25 vol%
(Iv) Volume ratio [(a) / [(b) + (c)]] of the crystalline resin (a) and the sum of the low melting point alloy (b) and the metal or alloy powder (c) : 2.0 to 30.0
(V) Volume ratio [(b) / (c)] of the low melting point alloy (b) and the metal or alloy powder (c): 1.0 to 4.0 The component (b) is an alloy containing Sn as a main component and containing at least one subcomponent selected from {Cu, Ni, Ag, Bi, Zn, Al, Mg},
The thermally conductive resin composition according to claim 1, wherein the component (c) is at least one metal or alloy selected from {Cu, Ni, Zn, Al, Fe}.   The thermally conductive resin composition according to claim 1 or 2, wherein the component (d) is at least one component selected from {graphite, aluminum oxide, magnesium oxide, aluminum nitride, boron nitride}. The component (a) is a polyphenylene sulfide resin having a melt viscosity (300 ° C., 1200 sec ⁻¹ ) of 50 Pa · sec or less,
The component (b) is an alloy containing Sn as a main component and including at least one subcomponent selected from {Cu, Ni, Ag, Bi, Zn},
The component (c) is a powder of at least one metal or alloy selected from {Cu, Ni, Zn},
The thermally conductive resin composition according to claim 1, wherein the component (d) is graphite and / or spherical alumina oxide.   The thermally conductive resin composition according to claim 4, wherein the component (d) is graphite surface-treated with an epoxy resin and / or spherical alumina oxide surface-treated with an organic silane.   The thermal conductivity of the thermal conductive resin composition is 4 W / mK or higher, the bending breaking strength is 100 MPa or higher, and the deflection temperature under load (low load) is 200 ° C. or higher. The heat conductive resin composition as described. It is a manufacturing method of the heat conductive resin composition in any one of Claims 1-6,
The crystalline resin (a), the low melting point alloy (b), the metal or alloy powder (c), the inorganic powder (d) and the fiber reinforcing material (e),
The manufacturing method of the heat conductive resin composition including the process of melt-kneading at the temperature which satisfy | fills the following conditions (1)-(3).
(1) Temperature at which the crystalline resin of component (a) is melted (2) Temperature above the solidus temperature of the low melting point alloy of component (b) (3) From the liquidus temperature of component (b) Temperature lower than 30 ℃   The molded article which consists of a heat conductive resin composition in any one of Claims 1-6.   A holding container for an optical pickup device comprising the thermally conductive resin composition according to any one of claims 1 to 6.   An optical pickup device comprising: the optical pickup device holding container according to claim 9; a light source; a light source control IC; an objective lens;   The holding container for optical semiconductors which consists of a heat conductive resin composition in any one of Claims 1-6.   The semiconductor thermal radiation container which consists of a heat conductive resin composition in any one of Claims 1-6.   The bearing which consists of a heat conductive resin composition in any one of Claims 1-6.

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