JP2013142513A - Heat radiation sheet for floor heating device, and floor heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat radiation sheet capable of improving efficiency and durability of a floor heating device.SOLUTION: A heat radiation sheet 9 includes an aluminum foil 9a, and an adhesive layer 9b disposed on the aluminum foil, the adhesive layer includes 100 pts.mass of an acrylic adhesive, and 1-20 pts.mass of an inorganic oxide filler including ≥50 mass% of alumina, a weight-average molecular weight Mw of the acrylic adhesive is 400,000-800,000, a ratio Mw/Mn of the weight-average molecular weight Mw and number-average molecular weight Nm is ≤5, and the inorganic oxide filler in the adhesive layer has a volume average particle size measured by a laser diffraction/scattering method, of 0.3-10 μm.

Description

  The present invention relates to a floor heating device heat radiation sheet and a floor heating device.

  As shown in Patent Documents 1 and 2, generally, in a floor heating apparatus, a synthetic resin pipe is provided in a pipe groove having a U-shaped cross section provided on a heat insulating plate, and hot water is allowed to flow through the pipe. By heating. On the heat insulating plate, a heat radiating sheet made of an aluminum foil provided with an adhesive layer is attached so as to cover the piping groove, whereby heat from the piping is uniformly dissipated. Moreover, a floor board is provided on the heat dissipation sheet via an adhesive or a release agent.

JP 2008-185244 A JP 2009-103372 A

The floor heating apparatus as described above is required to have higher efficiency and higher durability.
This invention is made | formed in view of such a situation, and provides the thermal radiation sheet which can improve the efficiency and durability of a floor heating apparatus.

  According to the present invention, an aluminum foil and an adhesive layer provided on the aluminum foil are provided, and the adhesive layer is an inorganic oxide containing 100 parts by mass of an acrylic adhesive and 50% by mass or more of alumina. The acrylic pressure-sensitive adhesive containing 1 to 20 parts by mass of filler has a weight average molecular weight (Mw) of 400,000 to 800,000 and a ratio Mw / Mn of the weight average molecular weight (Mw) to the number average molecular weight (Mn). Is 5 or less, and the inorganic oxide filler in the pressure-sensitive adhesive layer is provided with a heat dissipation sheet having a volume average particle diameter of 0.3 to 10 μm as measured by a laser diffraction scattering method.

  In a general floor heating device, even when hot water of 60 ° C. or more flows in the pipe, the temperature on the floor board is about 30 ° C., but the heat from the pipe is not necessarily efficiently transmitted to the floor board. Absent. Although it is considered that there are various factors of this inefficiency, the present inventors have found that the low thermal conductivity of the pressure-sensitive adhesive layer of the heat radiating sheet is a factor of inefficiency. And the inorganic oxide filler which has an alumina as a main component in this adhesive layer succeeds in improving the heat conductivity of an adhesive layer by mixing 1 mass part or more with respect to 100 mass parts of acrylic adhesives. did.

  However, although the thermal conductivity is improved by the addition of the inorganic oxide filler, when added in a large amount, when the heat-dissipating sheet is attached to the heat insulating plate, the adhesion decreases, and as a result, from the piping to the aluminum foil When the content of the inorganic oxide filler was 20 parts by mass or less with respect to 100 parts by mass of the acrylic pressure-sensitive adhesive, it was found that the thermal conductivity of the adhesive was lowered. It has been found that there is substantially no problem of deterioration.

  Furthermore, paying attention to the particle diameter of the filler, when the particle diameter is less than 0.3 μm, the effect of improving thermal conductivity is small, and when the particle diameter exceeds 10 μm, the adhesiveness is lowered.

  In addition, the piping of the floor heating device is generally made of a synthetic resin such as a cross-linked polyethylene resin, but when the present inventors paid attention to this piping, the portion in contact with the adhesive layer is slightly deteriorated. Was confirmed. And as a result of intensive studies to prevent this deterioration, the weight average molecular weight Mw of the acrylic pressure-sensitive adhesive is set to 400,000 to 800,000, and the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn is 5 or less. As a result, it was found that deterioration can be prevented, and the present invention has been completed.

  As described above, according to the present invention, heat can be efficiently transferred from the pipe to the aluminum foil by adding an inorganic oxide filler having an appropriate amount, composition, and average particle diameter, and appropriate Mw and Mw / Mn It turned out that deterioration of piping can be prevented by using the acrylic adhesive which has this. By using such a heat dissipation sheet, the efficiency and durability of the floor heating device can be improved.

FIG. 1 is a cross-sectional view showing a floor heating apparatus in which a heat dissipation sheet according to an embodiment of the present invention is used.

  Hereinafter, the heat dissipation sheet of one embodiment of the present invention will be described in detail.

<1. Floor heating system>
First, the state in which the heat radiating sheet according to one embodiment of the present invention is used in a floor heating apparatus will be described with reference to FIG. The floor heating device 1 includes a heat insulating plate 3, a pipe groove 5 having a U-shaped cross section provided in the heat insulating plate 3, a pipe 7 disposed in the pipe groove 5, and the pipe groove 5. 3 and a floor plate 13 disposed on the heat dissipation sheet 9 via an adhesive layer or a release agent layer 11. The heat dissipation sheet 9 includes an aluminum foil 9a and an adhesive layer 9b provided on the aluminum foil 9a, and is arranged so that the adhesive layer 9b is on the heat insulating plate 3 side.

<2. Insulation board>
The heat insulating plate is a plate-like member having heat insulating properties, and is made of, for example, a heat insulating material such as resin foam, wood, plywood, or a composite thereof. Resin foams include rigid polyurethane foams, polystyrene foams, crosslinked polyethylene foams, polypropylene foams, polyvinyl chloride foams, crosslinked rubber foams, thermosetting foams, and other highly rigid foams. Non-crosslinked polyethylene foams, polyvinyl acetate foams, non-crosslinked rubber foams, foams with low rigidity, such as high density polyethylene foams.

  The heat insulating plate is provided with a piping groove 5 having a U-shaped cross section. The width of the piping groove 5 is the same as or slightly larger than the diameter of the piping 7. The depth of the pipe groove 5 is the same as or slightly shallower than the outer diameter of the pipe 7. This is because in such a case, heat from the pipe 7 is efficiently transmitted to the heat dissipation sheet 9.

<3. Piping>
The pipe 7 is for flowing a heat transfer fluid for heating, and heat is released from the heat transfer fluid through the pipe wall to the outside. The pipe 7 is, for example, a metal pipe or a synthetic resin pipe, but the pipe 7 is preferably a synthetic resin pipe from the viewpoint of lightness and cost. Examples of the synthetic resin pipe include a crosslinked polyethylene pipe and a polybutene pipe. Since one of the problems of the present invention is to prevent the pipe 7 from being deteriorated, the effects of the present invention appear more remarkably when the pipe 7 is a synthetic resin pipe (especially a crosslinked polyethylene pipe) that is relatively easily deteriorated. The outer diameter of the pipe 7 is, for example, 5 to 30 mm, and the inner diameter is, for example, 3 to 20 mm. This is because in such a dimension, heat from the heat transfer fluid flowing in the pipe 7 is efficiently transmitted to the outside. Examples of the heat transfer fluid include warm water, water vapor, heated oil, antifreeze, heated air, and various types of heat exhaust gas, and warm water is preferable.

<4. Heat dissipation sheet>
The heat dissipation sheet 9 includes an aluminum foil 9a and an adhesive layer 9b provided on the aluminum foil 9a. The width and length of the heat dissipating sheet 9 are not limited and may be in the form of an elongated tape.

<4-1. Aluminum foil>
The aluminum foil 9a is provided to uniformly dissipate heat from the pipe 7 to the outside, and the thickness thereof is not particularly limited, but is preferably 5 to 100 μm. This is because if the aluminum foil is too thin, uniform heat release cannot be achieved, and if it is too thick, no further improvement in heat dissipation is observed, leading to an increase in cost.

<4-2. Adhesive layer>
The pressure-sensitive adhesive layer 9b includes an acrylic pressure-sensitive adhesive and an inorganic oxide filler. Specific examples of the acrylic pressure-sensitive adhesive include a homopolymer of (meth) acrylic acid ester or a copolymer with a copolymerizable monomer. Specific examples of (meth) acrylic acid esters include (meth) acrylic acid alkyl esters such as methyl ester, ethyl ester, butyl ester, 2-ethylhexyl ester, and octyl ester, dimethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, and the like. (Meth) acrylic acid alkylaminoalkyl ester, (meth) acrylic acid glycidyl ester, (meth) acrylic acid, itaconic acid, maleic anhydride, (meth) acrylic acid amide, (meth) acrylic acid N-hydroxyamide, etc. Can be mentioned. Specific examples of the copolymerizable monomer include vinyl acetate, styrene, acrylonitrile and the like.

  The weight average molecular weight (Mw) of the acrylic pressure-sensitive adhesive is 400,000 to 800,000. This is because the tackiness is not good if the weight average molecular weight is too small or too large. The weight average molecular weight (Mw) is 400,000, 500,000, 600,000, 700,000 and 800,000. This weight average molecular weight may be in the range between any two values exemplified herein. The ratio Mw / Mn of the weight average molecular weight (Mw) and the number average molecular weight (Mn) is 5 or less. When this ratio is larger than 5, the ratio of the low molecular weight polymer chain is too large, and as a result, the pipe 7 is likely to be deteriorated. By making this ratio Mw / Mn 5 or less, the deterioration of the pipe 7 can be prevented. Since the value of the ratio Mw / Mn is preferably as small as possible, the lower limit is not particularly specified. Specifically, the value of Mw / Mn is, for example, 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, and between any two of the numerical values exemplified here It may be within the range. The polystyrene equivalent weight average molecular weight and number average molecular weight can be determined by gel permeation chromatography (GPC). As the method for producing the acrylic pressure-sensitive adhesive, emulsion polymerization, solution polymerization and the like can be used.

  The pressure-sensitive adhesive layer 9b has low thermal conductivity in a state in which no inorganic oxide filler is contained, and therefore heat from the heat transfer fluid flowing through the pipe 7 is not efficiently transmitted to the aluminum foil. Therefore, the thermal conductivity of the pressure-sensitive adhesive layer 9b can be increased by adding an inorganic oxide filler having a high thermal conductivity to the pressure-sensitive adhesive layer 9b. The inorganic oxide filler added in the present invention is preferably made only of alumina from the viewpoint of improving thermal conductivity. However, even when a component other than alumina is contained, if the amount of alumina is 50% by mass or more, heat is added. The effect of improving conductivity is obtained. Specifically, the ratio of alumina in the inorganic oxide filler is, for example, 50, 60, 70, 80, 90, 95, 100 mass%, and is within the range between any two of the numerical values exemplified here. May be. Examples of inorganic oxide fillers other than alumina include fused silica, titanium oxide, and boron nitride.

  Content of an inorganic oxide filler is 1-20 mass parts with respect to 100 mass parts of acrylic adhesives. When the content is too small, the improvement in thermal conductivity is not sufficient, and when it is too large, the adhesive performance of the pressure-sensitive adhesive layer 9b deteriorates, and the adhesion between the heat insulating plate 3 and the aluminum foil 9a decreases, This is because the thermal conductivity is decreased. Specifically, the content of the inorganic oxide filler is 1, 2, 5, 10, 15, 20 parts by mass with respect to 100 parts by mass of the acrylic pressure-sensitive adhesive, and any of the numerical values exemplified here. It may be within a range between the two.

  The volume average particle diameter of the inorganic oxide filler measured by a laser diffraction scattering method is 0.3 to 10 μm. This is because if the average particle size is too small, the thermal conductivity is not sufficiently improved, and if it is too large, the adhesion between the heat insulating plate 3 and the aluminum foil 9a is lowered. The volume average particle diameter is preferably 1 to 8 μm. This is because in this case, both thermal conductivity and adhesion are particularly good. Specifically, the volume average particle diameter is, for example, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 μm, and any one of the numerical values exemplified here. It may be within a range between the two. In another expression, the volume average particle diameter of the inorganic oxide filler is, for example, 0.3 to 100% of the thickness of the pressure-sensitive adhesive layer 9b, and specifically, for example, 0.3, 1, 5, 10 , 20, 30, 40, 50, 60, 70, 80, 90, 100%, and may be within a range between any two of the numerical values exemplified here.

  Although the thickness of the adhesive layer 9b is not specifically limited, For example, it is 10-100 micrometers. If this thickness is too thin, the adhesiveness becomes insufficient, and the heat from the pipe 7 is difficult to be transferred to the aluminum foil. Specifically, the thickness of the pressure-sensitive adhesive layer 9b is, for example, 10, 20, 40, 60, 80, 100 μm, and may be within a range between any two of the numerical values exemplified here.

  The method of forming a pressure-sensitive adhesive layer on an aluminum foil to form a heat dissipation sheet is, for example, a method of directly applying the pressure-sensitive adhesive on the aluminum foil with a coater such as a gravure coater, comma coater, bar coater, knife coater, or roll coater. is there. The adhesive may be printed on the aluminum foil by letterpress printing, intaglio printing, planographic printing, flexographic printing, offset printing, screen printing, or the like.

<Adhesive layer or release agent layer>
Usually, an adhesive layer or a release agent layer 11 is disposed between the heat dissipation sheet 9 and the floor plate 13. This layer is provided in order to fix the floor board 13 with respect to the heat-radiation sheet 9, The composition is not specifically limited, For example, it is a urethane type adhesive agent.

<1. Manufacturing of heat dissipation sheet>
The heat-radiation sheet concerning an Example and a comparative example was manufactured with the following prescription. Table 1 shows the main formulations and the evaluation results. In Table 1, the mass part of the inorganic oxide filler is a value relative to 100 parts by mass of the acrylic pressure-sensitive adhesive.

<1-1. Aluminum foil>
Thickness 20μm

<1-2. Acrylic adhesive>
A copolymer of 80% by mass of butyl acrylate, 11% by mass of methyl methacrylate, 8% by mass of 2-hydroxyethyl methacrylate, and 1% by mass of acrylic acid.

<1-3. Inorganic oxide filler>
Alumina: manufactured by Denki Kagaku Kogyo Co., Ltd., trade name DAW-05, volume average particle diameter 5 μm
Alumina :: manufactured by Denki Kagaku Kogyo Co., Ltd., trade name ASFP-20, volume average particle size 0.3 μm
Alumina :: manufactured by Denki Kagaku Kogyo Co., Ltd., trade name DAW-07, volume average particle size 8.1 μm
Fused silica: manufactured by Denki Kagaku Kogyo Co., Ltd., trade name FB-7SDC, volume average particle size 5.8 μm
Titanium oxide: manufactured by Teika Co., Ltd., trade name “JR-1000”, volume average particle size 1.0 μm

<1-4. Production of heat dissipation sheet>
A mixture of the above-mentioned pressure-sensitive adhesive and inorganic oxide filler was applied to an aluminum foil so as to have a thickness of 10 μm to form a pressure-sensitive adhesive layer, thereby preparing a heat dissipation sheet.

<2. Evaluation of heat dissipation sheet>
A pipe groove having a U-shaped cross section having a depth of 10 mm and a width of 10 mm was formed on a heat insulating plate made of a crosslinked polyethylene foam and having a thickness of 10 mm and a width of 10 mm. . Next, the said heat dissipation sheet was affixed on this heat insulation board shape, and the floor board was affixed with the urethane type adhesive agent.

<2-1. Evaluation of thermal conductivity>
Hot water of 60 ° C. was poured into the piping, the temperature on the floor board surface was measured, and the following criteria were evaluated.
A: 38 ° C. or higher ○: 36 ° C. or higher and lower than 38 ° C. Δ: 34 ° C. or higher and lower than 36 ° C. x: lower than 34 ° C.

<2-2. Evaluation of adhesion>
In accordance with “Adhesive tape / adhesive sheet test method” defined in JIS Z0237, the adhesive strength (180 degree peeling adhesive strength) of the adhesive layer was measured, and the adhesiveness of the heat dissipation tape was evaluated according to the following criteria.
A: 10 N / 10 mm or more B: 5 N / 10 mm or more and less than 10 N / 10 mm Δ: 2 N / 10 mm or more and less than 5 N / 10 mm x: Less than 2 N / 10 mm

<2-3. Pipe deterioration evaluation>
Hot water of 60 ° C. was allowed to flow through the pipe for 100 hours, and then the floor plate and the heat radiating sheet were peeled off, and the presence or absence of deterioration of the pipe was visually evaluated.

<3. Summary>
As described above, the acrylic adhesive having an appropriate Mw and Mw / Mn can be efficiently transferred from the pipe to the aluminum foil by adding an inorganic oxide filler having an appropriate amount, composition and average particle size. It turned out that deterioration of piping can be prevented by using an agent. And it turned out that the efficiency and durability of a floor heating apparatus can be improved by using such a thermal radiation sheet.

Claims (2)

An aluminum foil, and an adhesive layer provided on the aluminum foil,
The pressure-sensitive adhesive layer includes 100 parts by mass of an acrylic pressure-sensitive adhesive and 1 to 20 parts by mass of an inorganic oxide filler containing 50% by mass or more of alumina.
The acrylic pressure-sensitive adhesive has a weight average molecular weight (Mw) of 400,000 to 800,000 and a ratio Mw / Mn of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 5 or less,
The inorganic oxide filler in the pressure-sensitive adhesive layer is a heat radiation sheet having a volume average particle diameter of 0.3 to 10 μm as measured by a laser diffraction scattering method. A heat insulating plate, a pipe groove having a U-shaped cross section provided in the heat insulating plate, a pipe disposed in the pipe groove, and a heat dissipation sheet provided on the heat insulating plate so as to cover the pipe groove, And a floor plate disposed on the heat dissipation sheet directly or via another layer, the heat dissipation sheet is the heat dissipation sheet according to claim 1, and the heat dissipation sheet has the pressure-sensitive adhesive layer as the heat insulating plate. A floor heating system arranged to be on the side.