JP5144329B2 - Foam sheet and manufacturing method thereof - Google Patents

Description

  The present invention relates to a foam sheet and a method for producing the same.

As a means for imparting heat insulation to a member that requires heat insulation, there is a method using a heat insulation material blended with a hollow microballoon. For example, a heat insulating material in which a microballoon made of borosilicate silica and a microballoon made of a phenol resin are blended with a resin component that is cured at a relatively low temperature such as an epoxy resin and has adhesiveness has been proposed (Patent Document 1). 2). The operation of applying such a heat insulating material to a member that requires heat insulation and drying is repeated several times to form a heat insulation layer, thereby imparting heat insulation.
Japanese Patent No. 2906083 Japanese Patent No. 2990534

  The heat-insulating composition containing the micro-balloon as described above can give high heat-insulating properties, but there is a problem in handling and workability because it is necessary to repeat application and drying. There is also a problem that the scene is limited. Insulation can be improved by increasing the amount of the microballoon, but if the amount of the microballoon, especially the amount of the microballoon mainly composed of borosilicate glass, is increased, the heat insulating layer The moldability, adhesiveness, flexibility, etc. of the resin are reduced, and there arises a problem that it is easy to peel off.

  An object of the present invention is to provide a foam sheet and a method for producing the same, which are excellent in heat insulation and flexibility, excellent in handleability, workability, and moldability, and applicable to various applications.

  In order to achieve the above object, the present invention provides the following foamed sheet and method for producing the same.

<1> For 100 parts by mass of thermoplastic polyurethane elastomer, 1 to 30 parts by mass of a microballoon composed mainly of borosilicate glass and 0.4 to 2.0 parts by mass of thermally expandable microcapsules are blended. The foam sheet is characterized in that the thermally expandable microcapsule is thermally expanded and formed into a sheet shape.

<2> A microballoon mainly composed of 5 to 20 parts by mass of borosilicate glass and 1.0 to 1.4 parts by mass of thermally expandable microcapsules are blended with 100 parts by mass of the thermoplastic polyurethane elastomer. and, foamed sheets you characterized in that the heat-expandable microcapsules is obtained by forming into a sheet causes a thermal expansion.

<3> 100 micro parts of thermoplastic polyurethane elastomer is blended with 1 to 30 parts by mass of a microballoon composed mainly of borosilicate glass and 0.4 to 2.0 parts by mass of thermally expandable microcapsules. A method for producing a foamed sheet, wherein the thermally expandable microcapsules are thermally expanded by an inflation method or a T-die method and are formed into a sheet shape.

<4> For 100 parts by mass of thermoplastic polyurethane elastomer, a microballoon mainly composed of 5 to 20 parts by mass of borosilicate glass and 1.0 to 1.4 parts by mass of thermally expandable microcapsules are blended. and, inflation method or T-die method by the method for producing a foamed sheet you characterized by forming said heat-expandable microcapsules in a sheet causes a thermal expansion.

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in heat insulation and a softness | flexibility, it is excellent in a handleability, workability | operativity, and a moldability, and the foamed sheet which can be applied to various uses and its manufacturing method are provided.

Hereinafter, the foamed sheet and the production method thereof according to the present invention will be specifically described.
The inventors of the present invention have made extensive studies to achieve the above object. As a result, a thermoplastic balloon is blended with a microballoon mainly composed of borosilicate glass and a thermally expandable microcapsule at specific ratios, respectively. By making the expandable microcapsules thermally expandable and forming into a foam sheet, it has excellent performance such as heat insulation, flexibility, heat shrinkage, dimensional stability, handleability, workability, moldability, etc. The present invention has been completed by finding that it can be applied to various applications.

-Thermoplastic elastomer-
Examples of the thermoplastic elastomer that is the main component (main component) of the foamed sheet according to the present invention include styrene, olefin, vinyl chloride, urethane, ester, and amide. Any of them can be used. In addition, from the viewpoints of moldability, expansion start temperature of the heat-expandable microcapsules, heat insulation, etc., those having a softening temperature in the range of 90 to 160 ° C. are preferable, and a plurality of types of thermoplastic elastomers may be blended as necessary. May be used.

  In particular, a thermoplastic polyurethane elastomer (hereinafter sometimes abbreviated as TPU) is preferably used because it is excellent in moldability, heat insulation, flexibility, lightness, chemical resistance, oil resistance, ozone resistance, and the like. Can do. If TPU is used as the main agent, it can be easily formed into a sheet by, for example, an inflation method or a T-die method, has extremely high heat insulation, is flexible, and has a specific gravity of 0.7 to 0.9. A sheet can be obtained.

TPU is a rubber-like elastic body having a urethane bond (—NHCOO—) in its molecular structure, and mainly includes ester systems (adipate type, caprolactone type, polycarbonate type, etc.) and ether systems. Either type can be used. A urethane silicone copolymer type or the like can also be used.
These TPUs can be obtained on the market, for example, BASF, ET880 (ether urethane), ET690 (ester urethane), C90 (ester urethane), DIC Bayer T-2180 (lactone urethane) ), T-1190 (ester urethane), Kuraray U8180, U1190, and the like, but are not limited thereto.

-Microballoon mainly composed of borosilicate glass-
A microballoon mainly composed of borosilicate glass (hereinafter sometimes referred to as a glass balloon) is a hollow microsphere mainly made of silica (SiO ₂ ), has a small loss on heating, and has high heat resistance. , Heat insulation, shape retention and the like. In the present invention, silica is contained in an amount of 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and can be uniformly mixed in the thermoplastic elastomer. Use those whose physical properties (shape, particle size, etc.) do not change due to heating during molding.

As specific properties, the average particle size is preferably 5 to 90 μm, more preferably 5 to 45 μm, the bulk specific gravity is 0.1 to 0.5 g / cm ³ , the true specific gravity is 0.2 to 0.7, and the pressure resistance strength. A glass balloon of 10 Mpa or more can be preferably used. Such glass balloons can be obtained on the market. For example, Q-CEL5070S and 7040S manufactured by Potters Ballotini Co., Ltd., Fuji Balloons S-35, S-40 and H- manufactured by Fuji Silysia Chemical Co., Ltd. 35 and the like, but are not limited thereto.

  The thermal insulation of a foam sheet can be effectively improved by mix | blending the above glass balloons with a thermoplastic elastomer. However, if the blending amount of the glass balloon is less than 1 part by mass with respect to 100 parts by mass of the thermoplastic elastomer, the heat insulation effect by the glass balloon cannot be sufficiently exhibited, or the effects of heat shrinkage and dimensional stability are poor. . On the other hand, as the amount of glass balloon is increased, the film formability and strength of the foamed sheet are reduced, and when it exceeds 30 parts by mass, the sheet cannot be formed or the strength of the sheet is significantly reduced. . Therefore, the compounding amount of the glass balloon is in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the thermoplastic elastomer, and within the above range depending on the heat insulation, flexibility, usage, etc. required for the foam sheet. What is necessary is just to determine suitably, Preferably it is 5-20 mass parts.

-Thermally expandable microcapsules-
Thermally expandable microcapsules are minute spheres encapsulating liquid, and the outer shell mainly composed of thermoplastic resin, and the softening temperature of the thermoplastic resin encapsulated in the outer shell and constituting the outer shell. It is comprised with the liquid which has the boiling point of.
The physical properties of the thermally expandable microcapsules are that they can be uniformly mixed in the thermoplastic elastomer that is the main component of the foam sheet of the present invention, and the thermal expansion is such that it does not rupture when the raw material composition is formed into a sheet. And what is necessary is just to be able to maintain the expanded shape after shaping | molding. Specifically, the average particle diameter before expansion of the thermally expandable microcapsule is preferably 5 to 50 μm, more preferably 20 to 40 μm, and the average particle diameter after expansion is preferably 50 to 160 μm, more preferably Is 80-120 μm. Further, a thermally expandable microcapsule having a thermal expansion start temperature of about 100 to 170 ° C., a maximum foaming temperature of about 160 to 200 ° C., and a volume expansion coefficient of about 50 to 100 times can be preferably used.

The material constituting the outer shell of the thermally expandable microcapsule as described above may be appropriately selected according to the softening temperature of the thermoplastic elastomer, the molding temperature when molding the raw material composition into a sheet, For example, homopolymers composed of monomers such as (meth) acrylonitrile, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylonitrile, methyl (meth) acrylate, Examples thereof include thermoplastic resins such as copolymers composed of two or more types of monomers such as ethyl (meth) acrylate and butyl (meth) acrylate. Further, for example, a thermal expansion microcapsule in which inorganic fine particles such as titanium oxide, zinc oxide, alumina, silica, calcium carbonate, etc. are fixed to the surface of a microcapsule made of a thermoplastic resin via a binder resin may be used. . In addition, a thermally expandable microcapsule whose outer shell is mainly formed of acrylonitrile and silicon, and those whose foaming (e.g., expansion coefficient) can be controlled by adjusting the blending amount of silicon can be used.
On the other hand, the encapsulated liquid is preferably a hydrocarbon that is vaporized when the raw material composition is molded, and examples thereof include low-boiling liquids such as normal butane, isobutane, normal pentane, isopentane, and petroleum ether.

  The thermally expandable microcapsules as described above can be obtained on the market. For example, Matsumoto Microsphere F-55, F-80S, F-80VS, F-82EVA50, F-85, Matsumoto Yushi Seiyaku Co., Ltd. F-100; EXPANCEL Co., Ltd. Expandel 092-40, 192-80, 092-120, 009-80, 092RMB120, 092MB120, 930DU120;

  When the amount of the thermally expandable microcapsule is less than 0.4 parts by mass with respect to 100 parts by mass of the thermoplastic elastomer, the heat insulating effect by the microcapsules after thermal expansion cannot be sufficiently exhibited. On the other hand, when the amount of the thermally expandable microcapsule exceeds 2 parts by mass, many microcapsules that are thermally expanded exist when the raw material composition is formed into a sheet, and bubbles are easily connected. This causes problems such as a decrease in strength and heat insulation, pinholes in the sheet, and increased surface roughness of the sheet. Therefore, the compounding amount of the heat-expandable microcapsule is within the range of 0.4 to 2.0 parts by mass with respect to 100 parts by mass of the thermoplastic elastomer, and the heat insulation, usage, etc. required for the foamed sheet after molding. However, it is preferably 1.0 to 1.4 parts by mass. If 100 parts by mass of the thermoplastic elastomer is blended with a thermally expandable microcapsule within a range of 1.0 to 1.4 parts by mass and molded into a sheet shape, a foamed sheet having a closed cell structure is obtained and strength is increased. In addition to its high thermal insulation and light weight, it can float on the water for a long time.

-Other ingredients-
The foamed sheet of the present invention contains the thermoplastic elastomer as described above, a glass balloon, and a thermally expandable microcapsule as essential components, but may contain other components (optional components) as necessary.
Optional components include, for example, foam accelerators, flame retardants, flame retardant aids, lubricants, heat stabilizers, plasticizers, pigments, dyes, UV absorbers, light stabilizers, antioxidants, coupling agents, and mold prevention agents. Agents, antistatic agents, inorganic fillers, pressure-sensitive adhesives, antiblocking agents, antibacterial agents, deodorants and the like. For example, if a phosphoric acid ester is used as a flame retardant, it can be made into a foam sheet having not only heat insulation but also fire resistance (heat resistance).
These optional components are preferably blended in such an amount that does not interfere with the effect of the foamed sheet of the present invention, in particular, to the extent that the heat insulating properties, flexibility, and film formability of the foamed sheet are not lowered. The total amount of the optional components is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass.

The method for producing the foamed sheet according to the present invention is not particularly limited, but can be suitably produced by an inflation method or a T-die method.
First, using the above essential components, 1 to 30 parts by mass, preferably 5 to 20 parts by mass of glass balloon, and 0.4 to 2.0 parts by mass, preferably 1 to 100 parts by mass of the thermoplastic elastomer. A raw material composition containing 0 to 1.4 parts by mass of a thermally expandable microcapsule and an appropriate amount of the optional component as required is prepared.
For example, the thermoplastic elastomer is heated and kneaded using a Henshur mixer, a Banbury mixer, a roll kneader, a pressure kneader, etc., and pelletized with a calendar roll, a single screw extruder, a twin screw extruder, etc. A balloon and a thermally expandable microcapsule are attached (blended) to obtain a raw material composition. The pellets using this as a master batch are formed into a foam sheet by T-die extrusion molding, inflation extrusion molding or the like.

  For example, in the case of molding by an inflation method, a thermoplastic elastomer is melted, the melted raw material composition is extruded into a cylindrical shape, and air is blown into it to expand it. Thereby, while being able to shape | mold into a sheet form, the foamed sheet in which the thermally expansible microcapsule was thermally expanded can be obtained. On the other hand, in the case of molding by the T-die method, the raw material composition is melted in the same manner as described above, and the molten raw material composition is extruded from a slit to be formed into a sheet shape, and the thermally expandable microcapsule is thermally expanded to obtain a foam sheet. It can be.

  In any of the molding methods, the heating temperature (molding temperature) when molding the raw material composition into a sheet is not less than the softening temperature of the thermoplastic elastomer as the main agent and the expansion start temperature of the thermally expandable microcapsules. Although it is necessary to make it above, if the temperature at the time of molding is too high, the thermally expandable microcapsules may expand too much, and the capsules may burst or the shape may collapse. The temperature at the time of molding depends on the expansion start temperature of the thermally expandable microcapsule used, but is preferable to the expansion start temperature in order to reliably expand the thermally expandable microcapsule while preventing bursting due to excessive expansion. Is preferably set in the range of 40 to 80 ° C, more preferably 50 to 70 ° C.

  In the raw material composition, the thermoplastic elastomer as the main ingredient is blended with a glass balloon and a heat-expandable microcapsule. Therefore, when melted and formed into a sheet, the outer shell of the capsule softens. When the liquid contained in the capsule is vaporized, the capsule expands several times to several tens of times to form hollow spherical particles. And when shape | molded in a sheet form, a capsule is maintained as a hollow spherical particle whose diameter is much larger than before expansion | swelling, and can show the high heat insulation effect.

  The thickness of the foam sheet may be determined according to its use, etc.In the case of inflation molding, it is adjusted by the thickness when extruding the molten raw material composition into a cylindrical shape, or the pressure when inflating by blowing air In the case of T-die molding, it can be adjusted by the interval of the slits. However, if the thickness of the sheet is too thin, the strength becomes low, and pinholes are likely to occur due to glass balloons or foamed microcapsules, and a sufficient heat insulation effect is obtained by exposing many bubbles to the surface of the sheet. There is a risk of not. From these viewpoints, the thickness of the foam sheet is preferably 50 to 600 μm, more preferably 100 to 500 μm.

As described above, the foam sheet according to the present invention includes a glass balloon and also includes a heat-expandable microcapsule, so that it has excellent moldability, is lightweight, and has excellent heat insulation, flexibility, dimensional stability, and the like. It will be.
Such foam sheet according to the present invention has various uses such as hose, tube, inner surface lining of fire hose, civil engineering / irrigation hose lining, conveyor belt, drive belt, electric wire coating, shoe sole, upper material, It can be suitably applied to automobile parts, watch bands, bag handles, elbow pads, synthetic leather, life jackets, wet suits, heat insulating sheets, anti-condensation sheets, roofing materials, bats, club grips, and vantages.

  Hereinafter, although an example and a comparative example are explained, the present invention is not restricted at all by these examples.

<Example 1>
A raw material composition for producing a foam sheet was prepared by the following components and blending.
・ Ether urethane 100 parts by mass (Elastolan ET880)
Thermal expansion microcapsules 1.4 parts by mass (Expancel 930DU120, average particle size 33 μm, thermal expansion start temperature: 122 ° C.)
・ Glass balloon 5.0 parts by mass (Q-CEL5020FPS, average particle size 35 μm)
-5.0 parts by weight of blocking inhibitor (AB-1, manufactured by Tokyo Ink)
・ 5.0 parts by weight of colorant (PEONY E, manufactured by Dainippon Ink & Chemicals, Inc.)

The above components were blended and mixed with a tumbler for 30 minutes to prepare a raw material composition.
This raw material composition was pelletized using a twin screw extruder. Next, the pellets were blown using an inflation extruder (trade name: EXT65, φ65 mm, L / D: 28, manufactured by Tommy Machine Industries Co., Ltd.), a die diameter of φ150 mm, an extruder cylinder temperature of 165 ° C., 170 ° C., 180 ° C., and a die temperature. Inflation extrusion was performed by inflating at 185 ° C. and a winding speed of 5 m / min, and a foamed sheet having a thickness of 386 μm was formed and wound with a winder.

<Examples 2 to 6>
A raw material composition having the components and blending amounts shown in Table 1 was prepared, and a foam sheet was produced by the inflation method in the same manner as in Example 1.

<Comparative Examples 1-2>
Moreover, the raw material composition which consists of a component shown in Table 1 and a compounding quantity was prepared, and the foamed sheet was manufactured by the inflation method by the method similar to Example 1. FIG.

< Reference Example 7 and Comparative Examples 3 to 4>
A raw material composition comprising the components and blending amounts shown in Table 2 was prepared, and a foamed sheet was produced by the inflation method in the same manner as in Example 1 except that the thickness was changed from that in Example 1.

  As shown in Tables 1 and 2, in Examples 1, 2 and 3, 5 to 20 parts by weight of glass balloons and 1.4 parts by weight of thermally expandable microcapsules were added to 100 parts by weight of TPU, and a foamed sheet. Was made. For comparison, a foamed sheet of Comparative Example 1 in which 1.4 parts by weight of thermally expandable microcapsules was added to 100 parts by weight of TPU was also prepared and subjected to comparative verification of physical strength. As a result, the foamed sheets obtained in Examples 1, 2, and 3 had a shrinkage rate of 1% or less in the heat shrink test (160 ° C., 1 hour), which is more heat resistant than the sheet obtained in Comparative Example 1. An excellent sheet could be obtained.

  In Examples 4, 5, and 6, foamed sheets were prepared by adding 10 parts by weight of glass balloons and 0.57 parts by weight to 2.0 parts by weight of thermally expandable microcapsules with respect to 100 parts by weight of TPU. For comparison, Comparative Example 2 in which 10 parts by weight of a glass balloon was added to 100 parts by weight of TPU was also produced, and the same comparative verification was performed. As a result, in Examples 4, 5, and 6 in which a predetermined amount of thermally expandable microcapsules was further added to the composition of Comparative Example 2, the shrinkage rate of the heat shrinkage test (160 ° C., 1 hour) was maintained and the heat insulating property was obtained. And a low specific gravity foam sheet could be obtained. The specific gravity of the sheet is proportional to the addition amount of the thermally expandable capsule, but if the addition amount exceeds 2 parts by weight, eyes will be formed in the lip mouth during the molding process, which will cause a decrease in film formability.

In Reference Example 7, a foamed sheet was prepared by adding 5 parts by weight of a glass balloon and 1.4 parts by weight of thermally expandable microcapsules to 100 parts by weight of a polyamide- based thermoplastic elastomer as a thermoplastic elastomer . As in the case of using TPU, a foamed sheet having a light weight and excellent thermal stability was obtained.

Claims (4)

For 100 parts by mass of the thermoplastic polyurethane elastomer, a microballoon mainly composed of 1 to 30 parts by mass of borosilicate glass and 0.4 to 2.0 parts by mass of thermally expandable microcapsules are blended, A foam sheet obtained by thermally expanding a thermally expandable microcapsule and forming it into a sheet shape. For 100 parts by mass of thermoplastic polyurethane elastomer, a microballoon mainly composed of 5 to 20 parts by mass of borosilicate glass and 1.0 to 1.4 parts by mass of thermally expandable microcapsules are blended, foamed sheets you characterized in that the thermally expandable microcapsule is obtained by forming into a sheet causes a thermal expansion. For 100 parts by mass of thermoplastic polyurethane elastomer, a microballoon composed mainly of 1 to 30 parts by mass of borosilicate glass and 0.4 to 2.0 parts by mass of thermally expandable microcapsules are blended, and inflation is performed. A method for producing a foamed sheet, wherein the thermally expandable microcapsules are thermally expanded by a method or a T-die method and are formed into a sheet shape. A 100% by mass thermoplastic polyurethane elastomer is blended with a microballoon composed mainly of 5 to 20 parts by mass of borosilicate glass and 1.0 to 1.4 parts by mass of thermally expandable microcapsules, and is inflated. Act or T-die method by the method for producing a foamed sheet you characterized by forming said heat-expandable microcapsules in a sheet causes a thermal expansion.