JP6382927B2 - Manufacturing method of resin molded products - Google Patents

Description

  The present invention relates to a method for producing a resin molded product, and more specifically, a filler for imparting functions such as thermal conductivity, conductivity, and wear resistance to a resin molded product such as a resin sheet. The present invention relates to a preferred method for producing a resin molded product oriented in the vertical direction.

  In recent years, electronic devices have rapidly become denser and thinner, and the influence of heat generated from ICs, power components, and high-brightness LEDs has become a serious problem. On the other hand, the use of thermally conductive resin molded products (sheets) is progressing as a member that efficiently transmits heat between the heat generator and the heat radiator. In addition to heat conductive resin sheets, examples of resin sheets with functional fillers oriented in the thickness direction include electrical contacts, conductive sheets used for wireless power feeding, etc., and slips used to prevent slipping during walking. Stop sheets and the like are known.

  For example, as a means for imparting a high thermal conductivity function to a resin, it is known that a thermal conductive filler is oriented and dispersed in the resin in order to efficiently form a thermal conduction path. For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 08-244094), a kneaded product containing resin and / or rubber and scale-like particles is extruded into a plurality of strip-shaped plastics, and these are assembled with a lip to form a sheet. A manufacturing method for post-curing or curing while forming into a sheet has been proposed.

  Further, for example, in Patent Document 2 (Japanese Patent Application Laid-Open No. 2010-132866), the surface direction of graphite particles and / or hexagonal boron nitride particles, the major axis direction of an ellipse, or the major axis direction of a rod is the heat conduction. A thermally conductive resin sheet oriented in the thickness direction of the conductive resin sheet is disclosed.

  Here, in order to efficiently release heat from the heat generating element to the heat radiating element, it is desirable to manufacture a heat conductive resin sheet in which the heat conductive filler is highly oriented in the thickness direction. For example, in Patent Document 3 (Japanese Patent Application Laid-Open No. 60-219034), a sheet in which short fiber groups are oriented and embedded in the sheet longitudinal direction in an elastic sheet is cut in the sheet width direction in a direction perpendicular to the sheet surface. There has been proposed a method for producing a sheet in which a group of strip-shaped pieces is formed and fillers are oriented in the thickness direction formed by joining side surfaces of the strip-shaped pieces.

  Moreover, also in patent document 4 (Unexamined-Japanese-Patent No. 2012-23335), the said heat conductive filler is obtained by extruding the heat conductive composition containing a polymer, a heat conductive filler, and a filler with an extruder. An extrusion process for forming an extruded product oriented along the extrusion direction, a curing process for curing the extrusion product to obtain a cured product, and the cured product perpendicular to the extrusion direction using an ultrasonic cutter The manufacturing method of the heat conductive resin sheet which contains the cutting process cut | disconnected to predetermined thickness in a direction at least is disclosed.

Japanese Patent Laid-Open No. 08-244094 JP 2010-132866 A JP-A-60-219034 JP 2012-23335 A

  However, in the prior art described in the above patent document, the resin sheet manufacturing process is complicated, and the equipment and the number of processing steps increase due to the lamination process and the cutting process. In particular, a press is indispensable in the laminating process, and there is a problem that continuous moldability is impaired and it is not possible to cope with mass production.

  In view of the above problems in the prior art, an object of the present invention is to provide an efficient method for producing a resin molded product in which fillers are oriented in the thickness direction of the resin molded product.

  In order to solve the above-mentioned problems, the present inventor conducted extensive research on a method for producing a resin molded product. As a result, by folding the resin molded product in which the filler is oriented in the vertical direction inside the T-die, the filler is added in the thickness direction. The present inventors have found that an oriented molded product can be obtained efficiently and have reached the present invention.

That is, the present invention
A method for producing a resin molded article using a T die having a first gap of continuous gaps X in the vertical direction and a second gap of gaps Y in the vertical direction (where X <Y) and fillers oriented in the thickness direction Because
A first step of obtaining a resin molding precursor containing the filler oriented in the plane direction by passing the resin composition of the resin molded product containing the filler through the first gap;
On the downstream side of the first gap, after changing the flow of the resin molding precursor that has passed through the first gap in the vertical direction with respect to the extrusion direction, when passing through the second gap, A second step of obtaining a resin molded product by fusing the resin molding precursor in which the filler is oriented in a direction substantially perpendicular to the direction of flow in the gap ;
Have
Having an inclined surface on at least one of the upper and lower sides between the first gap and the second gap;
The manufacturing method of the resin molded product characterized by this is provided.

  The inclination angle of the inclined surface is preferably 10 to 50 °, and the first gap is preferably 0.1 mm or more and 5.0 mm or less.

  As the filler, various conventionally known materials can be used as long as the effects of the present invention are not impaired, but the volume filling factor of the filler in the resin composition is preferably 30 to 70% by volume. Further, the higher the thermal conductivity of the filler is, the more preferable, and at least higher than the resin of the base material is desired. Moreover, it is preferable that the aspect ratio of a filler is 2 or more from a viewpoint of orienting a filler in resin efficiently.

  According to the manufacturing method having such a configuration, the resin molding precursor in which the filler is oriented in the plane direction is fused inside the T die while being folded in a direction substantially perpendicular to the extrusion direction, and the filler is very efficiently used. It is possible to produce a resin molded product in which is oriented in the thickness direction.

  ADVANTAGE OF THE INVENTION According to this invention, the efficient manufacturing method of the resin molded product (For example, a sheet | seat, a board | plate material, a bar, a tube, a housing | casing etc.) in which the filler orientated in the thickness direction can be provided. More specifically, according to the present invention, it is possible to provide an efficient manufacturing method of a thermally conductive resin sheet, a conductive resin sheet, or an anti-slip resin sheet in which fillers are oriented in the thickness direction. .

It is a key map (side view of a T die) of a manufacturing method of a resin sheet of the present invention. 2 is an overview photograph of a resin sheet manufactured in Example 1. FIG. 2 is a cross-sectional SEM photograph of the resin sheet produced in Example 1. 2 is a cross-sectional SEM photograph of a resin sheet produced in Example 2.

  Hereinafter, among the preferred embodiments of the method for producing a resin molded product of the present invention, the case where the resin molded product is a heat conductive resin sheet will be described in detail with reference to the drawings. It is not limited to. In the following description, the same or corresponding parts are denoted by the same reference numerals, and redundant description may be omitted. Further, since the drawings are for conceptually explaining the present invention, the dimensions and ratios of the components shown may be different from the actual ones.

  FIG. 1 is a conceptual diagram of a method for producing a resin sheet of the present invention, and shows a schematic cross-sectional view of a tip portion of an extruder and a T die. The resin composition of the resin sheet containing the heat conductive filler is stirred and kneaded by the screw 2 and introduced into the first gap 4 (gap X) along the flow path 8.

  The flow of the resin composition is squeezed in the vertical direction (thickness direction) by the first gap 4 to form a thin strip shape. When passing through the first gap 4, a shearing force acts on the resin composition, and the thermally conductive filler mixed in the resin is oriented in the flow direction of the resin composition. In this case, the thermally conductive filler is oriented in the surface direction of the resin sheet precursor.

  Here, the gap of the first gap 4 is preferably 0.5 mm or more and 5.0 mm or less. If the gap of the first gap 4 is smaller than 0.5 mm, not only the extrusion pressure rises unnecessarily, but also resin clogging occurs. On the other hand, when the gap of the first gap 4 is larger than 5.0 mm, the degree of orientation of the thermally conductive filler with respect to the surface direction of the resin sheet precursor is reduced.

  When the thin resin sheet precursor in which the heat conductive filler is oriented in the flow direction of the resin composition completely passes through the first gap 4, the cross-sectional area of the flow path 8 is enlarged, and the length in the vertical direction is increased. Therefore, the flow of the resin sheet precursor changes in the vertical direction with respect to the extrusion direction. Thereafter, when the resin sheet precursor passes through the second gap 6, the resin sheet precursor is fused while being folded in a direction substantially perpendicular to the flow direction in the first gap 4, and the resin sheet is molded.

  Here, the gap Y of the second gap 6 is preferably not less than 2 times and not more than 20 times the gap X of the first gap 4. When the gap of the second gap 6 is smaller than twice the gap of the first gap 4, since the resin sheet precursor is not folded, the thermally conductive filler is not oriented in the thickness direction of the resin sheet. On the other hand, when the gap of the second gap 6 is larger than 10 times the gap of the first gap 4, the resin sheet precursor is not folded properly and partially turbulent, resulting in the thickness direction of the resin sheet. The proportion of the thermally conductive filler that is oriented in the direction will decrease. From the viewpoint of easily folding the resin sheet precursor in the thickness direction, the center in the thickness direction of the gap X of the first gap 4 and the center in the thickness direction of the gap Y of the second gap 6 are substantially the same. It is preferable to set the position.

  The shape of the opening in the first gap 4 is not particularly defined, but the upstream side surface is preferably an inclined surface so that the pressure loss is small, and the thermally conductive filler is most efficiently applied to the downstream side surface of the resin sheet. In order to align in the thickness direction, it is desirable to adjust the tilt angle. As said inclination-angle, it can be set as 10 degrees-50 degrees, for example, Furthermore, it is preferable that it is 20 degrees-25 degrees. Moreover, it is not necessary to have an inclination on both sides, and only one of them may have an inclination. Note that the depths of the openings of the first gap 4 and the second gap 6 (that is, the gap between the first gap 4 and the second gap 6 in the direction substantially perpendicular to the paper surface in FIG. 1) are substantially the same throughout the T die. It is. Moreover, the width of the opening in the first gap and the second gap is not particularly defined, and various design changes can be made according to the product width of the resin sheet.

  As the resin, various conventionally known thermoplastic resins, thermoplastic elastomers, or polymer alloys thereof can be used as long as the effects of the present invention are not impaired. There is no restriction | limiting in particular as a thermoplastic resin, According to the objective, it can select suitably, For example, ethylene-alpha-olefin copolymers, such as polyethylene, a polypropylene, an ethylene propylene copolymer; Polymethylpentene, polychlorination Fluorine resins such as vinyl, polyvinylidene chloride, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyacetal, polyvinylidene fluoride, polytetrafluoroethylene; polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polystyrene, Polyacrylonitrile, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer (ABS) resin, polyphenylene ether, modified polyphenylene ether, aliphatic polyamide , Aromatic polyamides, polyamideimide, polymethacrylic acid or its ester, polyacrylic acid or its ester, polycarbonate, polyphenylene sulfide, polysulfone, polyethersulfone, polyethernitrile, polyetherketone, polyketone, liquid crystal polymer, silicone resin And ionomers. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the thermoplastic elastomer include a styrene-based thermoplastic elastomer such as a styrene-butadiene copolymer or a hydrogenated polymer thereof, a styrene-isoprene block copolymer or a hydrogenated polymer thereof, an olefin-based thermoplastic elastomer, and a vinyl chloride-based thermoplastic. Examples thereof include elastomers, polyester-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, and polyamide-based thermoplastic elastomers. These may be used individually by 1 type and may use 2 or more types together.

  In addition to the above-mentioned resins, reinforcing agents, fillers, softeners, plasticizers, cross-linking agents, cross-linking accelerators, cross-linking accelerators, anti-aging agents, tackifiers, antistatic agents, kneading adhesives, hardeners General blending / additives such as a flame retardant and a coupling agent can be arbitrarily selected.

  As an example of the heat conductive filler, conventionally known various materials can be used as long as the effects of the present invention are not impaired. For example, boron nitride (BN), graphite, carbon fiber, mica, alumina, aluminum nitride, Examples thereof include silicon carbide, silica, zinc oxide, molybdenum disulfide, copper, and aluminum, but boron nitride (BN), graphite, carbon fiber, and carbon nanotube (CNT) are preferably used from the viewpoint of excellent heat conduction effect. .

  There is no restriction | limiting in particular as a shape of a heat conductive filler, According to the objective, it can select suitably, For example, scale shape, plate shape, film | membrane shape, cylindrical shape, prismatic shape, elliptical shape, flat shape etc. are mentioned. However, the aspect ratio is preferably 2 or more from the viewpoint of forming a heat conduction path and from the viewpoint of being easily oriented in the resin. Moreover, the ratio of the heat conductive filler with respect to resin can be 20-80 volume%, and can be suitably determined according to the heat conductivity etc. which are required. In addition, when the ratio of a heat conductive filler is less than 20 volume%, a heat conductive effect becomes small. When the proportion of the heat conductive filler exceeds 80% by volume, the resin sheet precursor is folded in a direction substantially perpendicular to the direction of flow in the first gap when passing through the first gap, but between the resins. This makes it difficult to fuse. Therefore, in order to enhance the heat conduction effect of the resin sheet and facilitate extrusion, the ratio of the heat conductive filler to the resin base material is preferably 30 to 70% by volume, and 50 to 65% by volume. More preferably.

  As mentioned above, although typical embodiment of this invention was described, this invention is not limited only to these, Various design changes are possible, and such a design change is also contained in this invention. For example, the filler having various characteristics other than the thermal conductivity can be naturally used to orient the filler in the thickness direction of the resin sheet. Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

Example 1
In the formulation shown in Table 1, boron nitride (BN) filler (momentive: TP110), peroxide cross-linking agent (Nippon Yushi: Peroximon F100 5 parts by weight) with respect to fluororubber (Asahi Glass: Aphras 150L 100 parts by weight), And a crosslinking accelerator were kneaded with two rolls to prepare a ribbon sheet. The volume fraction of boron nitride (BN) filler with respect to fluororubber was 60%. The maximum size of the boron nitride (BN) filler was 150 μm. Here, the maximum size value of the boron nitride (BN) filler means the maximum value of the filler diameter.

  Next, a sheet having a thickness of 10 mm was produced from the ribbon sheet using a vertical alignment mold having a first gap of 1 mm and a second gap of 10 mm using a short axis extruder for rubber. A minute cross-linking treatment was applied. The sheet was sliced to prepare a heat conduction measurement sheet having a thickness of 100 μm. The thermal conductivity of the sheet was measured with an eye phase mobile 1μ manufactured by Eye Phase. The obtained thermal conductivity is as shown in Table 1. The thermal conductivity does not depend on the sheet thickness (the thermal resistance is inversely proportional to the thickness).

  An overview of the sheet after passing through the vertical mold is shown in FIG. When the sheet that has passed through the first gap passes through the second gap, it can be confirmed that the resin sheet has been molded by being fused while being folded in a direction substantially perpendicular to the direction of flow in the first gap. .

  A cross-sectional SEM photograph of the sheet obtained in Example 1 is shown in FIG. It can be confirmed that the boron nitride (BN) filler is oriented in the thickness direction of the sheet (up and down direction of the SEM photograph), and a sheet in which the filler is highly oriented in the thickness direction is obtained. For SEM observation, a scanning electron microscope (S-4800) manufactured by HITACHI was used.

<< Example 2 >>
In the formulation shown in Table 1, carbon fiber (CF, Teijin Limited: Lahima RA301), cross-linking agent, and cross-linking accelerator are kneaded with two rolls into H-NBR (ZEON / Zetpol 1036 50%). A ribbon sheet was obtained. The volume fraction of carbon fiber relative to the base polymer was 50%. The maximum size of the carbon fiber was 800 μm. Here, the maximum size of the carbon fiber means the maximum value (fiber length) in the fiber longitudinal direction.

  Next, the ribbon sheet was produced in a short axis extruder for rubber using a vertical alignment mold having a first gap of 0.5 mm and a second gap of 1 mm, and a sheet having a thickness of 1 mm was produced at 180 ° C. Was subjected to a crosslinking treatment for 10 minutes. The sheet was sliced to prepare a heat conduction measurement sheet having a thickness of 100 μm. The thermal conductivity of the sheet was measured with an eye phase mobile 1μ manufactured by Eye Phase. The obtained thermal conductivity is as shown in Table 1.

  A cross-sectional SEM photograph of the sheet obtained in Example 2 is shown in FIG. It can be confirmed that the carbon fiber is oriented in the thickness direction of the sheet (the vertical direction of the SEM photograph), and a sheet in which the filler is highly oriented in the thickness direction is obtained. For SEM observation, a scanning electron microscope (S-4800) manufactured by HITACHI was used.

Example 3
In the composition shown in Table 1, carbon fiber (CF, Nippon Graphite Fiber Co., Ltd .: Granock XN100 (3 mm)), peroxide cross-linking agent (Emerging Ouchi) with respect to acrylic rubber (NOK: A5098 100 parts by weight) Chemical Industry Co., Ltd .: Balnock ABS 2 parts by weight) and a crosslinking accelerator were kneaded with two rolls to obtain a ribbon sheet. The volume fraction of carbon fiber relative to the base polymer was 60%. The maximum size of the carbon fiber was 3 mm. Here, the maximum size of the carbon fiber means the maximum value (fiber length) in the fiber longitudinal direction.

  Next, the ribbon sheet was produced in a short axis extruder for rubber using a vertical alignment mold having a first gap of 0.5 mm and a second gap of 1 mm, and a sheet having a thickness of 1 mm was produced at 180 ° C. Was subjected to a crosslinking treatment for 10 minutes. The sheet was sliced to prepare a heat conduction measurement sheet having a thickness of 100 μm. The thermal conductivity of the sheet was measured with an eye phase mobile 1μ manufactured by Eye Phase. The obtained thermal conductivity is as shown in Table 1.

Example 4
In the composition shown in Table 1, carbon fiber (CF, Nippon Graphite Fiber Co., Ltd .: Granock XN100 (3 mm)) and crosslinking with respect to silicone resin (100 parts by weight of silicone rubber DY32 1005U manufactured by Toray Dow Corning Co., Ltd.) The agent (RC-4 50P FD 5 parts by weight manufactured by Toray Dow Corning Co., Ltd.) was kneaded with two rolls to obtain a ribbon sheet. The volume fraction of the pitch-based carbon fiber filler relative to the silicone resin was 65%. The pitch-based carbon fiber filler used had a length of 3000 μm.

  Next, a 1 mm thick sheet was produced from the ribbon sheet with a short axis extruder for rubber using a vertical alignment mold having a first gap of 1.0 mm and a second gap of 10 mm. Was subjected to a crosslinking treatment for 10 minutes. The sheet was sliced to prepare a heat conduction measurement sheet having a thickness of 100 μm. The thermal conductivity of the sheet was measured with an eye phase mobile 1μ manufactured by Eye Phase. The obtained thermal conductivity is as shown in Table 1.

The thermal conductivity in the thickness direction of the sheet shown in Table 1 has a high value of 15 to 80 W / mK, and high thermal conductivity is achieved by efficiently orienting the filler in the thickness direction of the sheet using the present invention. It can be seen that a heat radiating sheet having a rate can be easily produced.

Claims (4)

A method for producing a resin molded article using a T die having a first gap of continuous gaps X in the vertical direction and a second gap of gaps Y in the vertical direction (where X <Y) and fillers oriented in the thickness direction Because
A first step of obtaining a resin molding precursor containing the filler oriented in the plane direction by passing the resin composition of the resin molded product containing the filler through the first gap;
On the downstream side of the first gap, after changing the flow of the resin molding precursor that has passed through the first gap in the vertical direction with respect to the extrusion direction, when passing through the second gap, A second step of obtaining a resin molded product by fusing the resin molding precursor in which the filler is oriented in a direction substantially perpendicular to the direction of flow in the gap ;
Have
Having an inclined surface on at least one of the upper and lower sides between the first gap and the second gap;
A method for producing a resin molded product characterized by   The method for producing a resin molded product according to claim 1, wherein an inclination angle of the inclined surface is 10 to 50 °. The first gap is 0. It is 5 mm or more and 5.0 mm or less, The manufacturing method of the resin molded product of Claim 1 or 2 characterized by the above-mentioned. The volume filling factor of the filler in the resin composition is 30 to 70% by volume;
The manufacturing method of the resin molded product in any one of Claims 1-3 characterized by these.