JP2001020511A - Heat insulation material for floor heating and floor heater using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure strength by specifying a ration of the minimum value to the maximum value of 5% compressive strength within a specified temperature range in a heat insulating material formed of synthetic resin foam body. SOLUTION: A heat insulating material 5 for floor heating is laid between a heat resisting flooring 4 and permanent plywood 2, and a hot water pipe 5 as a heating means is accommodated in a groove 51 of the upper surface of the heat insulating material 5 to constitute a floor heater. Secondary, the heat insulating material 5 is formed of synthetic resin foam body, and the ratio S2/S1 of the minimum value S1 to the maximum value S2 of compressive strength at an environment temperature of 0 to 70 deg.C is set to 2 or less. Subsequently, in the case of thermoplastic polyester resin, at least one kind of component selected from the group consisting of isophthalic acid and cyclohexandimethanol is contained by 0.5 to 10 wt.% in gross, and preliminary foam particles are foamed and formed in a mold to set the crystallinity to 20 to 40% and set the fusion rate to at least 40%. Thus, the strength can be secured substantially constant regardless of temperature, and under high temperature environment, local drop can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a floor heating insulation material incorporated in a floor heating device and a floor heating device using the same.

[0002]

2. Description of the Related Art In recent years, floor heating devices that directly warm a floor with hot water, electric heating, or other heating means have become widespread as lifestyles have changed from living mainly in tatami to living in so-called flooring, chairs and tables. I am doing it. In such a floor heating device, a heat insulating material is incorporated in order to prevent heat from escaping downward (outdoor) from the heating means and to efficiently heat the floor from above (indoor).

Conventionally, glass wool or the like has been used as a heat insulating material. However, recently, in consideration of reducing the burden on the building by reducing the weight of the entire floor heating device and improving the efficiency of construction work, polypropylene and the like have recently been used. Use of an olefin-based resin foam as the heat insulating material has been studied (see, for example, JP-A-11-132476).

[0004]

According to studies made by the inventors, however, the above-mentioned olefin resin foam is excellent in light weight, crack resistance, heat insulation, chemical resistance, etc. The strength, especially the compressive strength, has a large temperature dependence, and the compressive strength greatly decreases with the temperature rise in the temperature range of about 0 to + 70 ° C. It has been clarified that, under an increased environment, the compression strength is greatly reduced, and for example, the floor around the place where the furniture is placed may be locally dropped.

Further, the floor heating device using the above-mentioned olefin-based resin foam also has a problem that the walking sensation when walking on the floor is deteriorated for the above-mentioned reason. A main object of the present invention is to provide an improved heat insulating material for floor heating, which has a substantially constant strength irrespective of temperature and is therefore less likely to cause a local drop particularly in a high-temperature environment. Another object of the present invention is to provide a floor heating device having a good walking feeling.

[0006]

Means for Solving the Problems The inventors have studied what kind of temperature-compressive strength characteristics the heat insulating material needs to have in order to prevent the above-mentioned local fall of the floor. did. As a result, if the ratio S ₂ / S ₁ between the minimum value S ₁ and the maximum value S ₂ of the 5% compressive strength in the above-mentioned environmental temperature range of 0 to + 70 ° C. is 2 or less, especially in a high-temperature environment The present inventors have found that a good feeling of walking can be obtained by preventing a local fall of the floor in the above, and have completed the present invention.

Therefore, the heat insulating material for floor heating according to the present invention has a ratio S ₂ / S ₁ between the minimum value S ₁ and the maximum value S ₂ of the 5% compressive strength in the temperature range of 0 to + 70 ° C. 2 It is characterized by being made of the following synthetic resin foam. Further, a floor heating device of the present invention includes the above-described heat insulating material for floor heating of the present invention, and heating means.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below. <Heat insulation material for floor heating> The heat insulation material for floor heating of the present invention is formed entirely of a synthetic resin foam, and the temperature of the foam in an environmental temperature range of 0 to + 70 ° C. the minimum value of 5% compression strength S ₁ and ratio S ₂ / S ₁ between the maximum value S ₂ is the need of 2 or less as.

In the case where the ratio S ₂ / S ₁ exceeds 2, as described above, the compressive strength is greatly reduced under the environment where the temperature is temporarily increased at the start of the operation of the floor heating device, and However, there is a problem that a person is locally depressed, and as a result, walking feeling is deteriorated. Note the S ₂ / S ₁ is 1.
It is preferably 5 or less, and more preferably 1.1 or less.

The lower limit of the ratio S ₂ / S ₁ is, of course, _{1 when the} minimum value S ₁ is equal to the maximum value S ₂ . There are various types of synthetic resin foams that can form a heat insulating material that satisfies such temperature-compressive strength characteristics. In particular, foamed molded articles obtained by in-mold foaming of pre-expanded particles of a thermoplastic polyester resin are preferably used. Is done.

The foamed molded article of the thermoplastic polyester resin satisfies the above-mentioned temperature-compression strength characteristics, is lightweight, and is excellent in shock absorption, repeated compression set, chemical resistance and the like. Further, the foamed molded article of the thermoplastic polyester-based resin has dimensional stability, particularly in a high-temperature environment,
It has excellent dimensional stability over a long period of time, has the advantage that it is difficult to form a gap with a floor material or the like due to heat shrinkage, and can form a heat insulating material that can sufficiently withstand long-term use. <Floor heating device> The floor heating device of the present invention, in which the above-described heat insulating material for floor heating of the present invention is incorporated, has various conventionally known configurations except that the heat insulating material for floor heating and the heating means are provided. be able to. One example is shown in FIG.

The floor heating apparatus in the example shown in FIG. 1 is supported on a joist 1 of a building via a discarded plywood 2 and a small joist 3 under a heat-resistant flooring 4 forming a floor. In the gap formed between the heat-resistant flooring 4 and the discarded plywood 2 by the small joist 3, the heat insulating material 5 for floor heating of the present invention is spread, and in the groove 51 formed on the upper surface side of the heat insulating material 5, It houses a pipe 6 for circulating a fluid such as hot water as a heating means.

In the drawings, reference numeral 7 denotes a soaking plate made of metal foil or the like, and reference numeral 8 denotes an auxiliary heat insulating material.
Since the auxiliary heat insulating material 8 is disposed below the discarded plywood 2 and does not require strength, it is preferable to form it with a normal resin foam such as a polystyrene resin foam in consideration of economy and the like. preferable. In the floor heating device of the above example, the heat insulating material 5 for floor heating spread under the heat-resistant flooring 4 has almost constant strength regardless of the temperature as described above, Since it does not easily cause a serious depression, the walking feeling when walking on it is excellent.

The configuration of the floor heating device is not limited to the example shown in the figure, and various conventionally known configurations are adopted except that the floor heating insulating material 5 and the heating means are provided as described above. It is possible to Moreover, the shape of the heat insulating material 5 for floor heating is as follows.
It can be changed as appropriate according to the configuration of the floor heating device.

For example, when a planar heating element such as electric heating is used as the heating means, the heat insulating material 5 may be formed as a simple flat plate having an appropriate thickness without the grooves 51 and the like. Further, the heat insulating material 5 may be formed with a through hole or the like for avoiding a small joist of a building in which the floor heating device is incorporated. In addition, appropriate design changes can be made without changing the gist of the present invention. <Thermoplastic polyester-based resin> The thermoplastic polyester-based resin forming the foamed molded article preferably used for the heat insulating material in the present invention is synthesized, for example, by subjecting terephthalic acid and ethylene glycol to a polycondensation reaction. Conventionally known various thermoplastic polyester resins represented by polyethylene terephthalate (PET)
Both can be used.

However, conventional thermoplastic polyester resins such as PET described above generally have high gas barrier properties and require a great deal of time to impregnate a foaming agent. Therefore, the resin is impregnated with a foaming agent (impregnation step). Then, the pre-expanded particles are obtained by heating and pre-expanding the particles to obtain pre-expanded particles (pre-expansion step). The pre-expanded particles are filled in a mold, expanded by heating, and subjected to foam molding (in-mold expansion step). If a foam molded body, that is, a heat insulating material for floor heating in this case, is manufactured by a conventional foam molding method, time, cost, and labor may be required.

Further, the above-mentioned conventional thermoplastic polyester resin tends to be easily crystallized by heating, that is, since the crystallization speed is high, the crystallinity of the pre-expanded particles is excessively increased by the heating during the impregnation or pre-expansion. Become higher,
There is also a problem that during the in-mold foam molding, the foaming fusion property between the foamed particles is reduced. For this reason, using a general-purpose foam molding machine, for example, a gauge pressure of steam of 0.5M
By foam molding under ordinary molding conditions such as Pa or less, although a foam molded article excellent in heat resistance can be obtained, the foamed particles are fused well with a high fusion rate, integrated, the compressive strength, etc. It is not possible to produce a foam molded article having excellent strength.

Therefore, in order to produce a foamed molded article having a high fusion rate using a conventional thermoplastic polyester resin such as PET, a special function such as a large amount of steam can be uniformly supplied into a mold. It is necessary to carry out molding under special molding conditions such that the gauge pressure exceeds 0.5 MPa using a special foam molding machine provided with. However, due to such special molding conditions, the foam molded article produced has an excessively high degree of crystallinity, for example, exceeding 40%, and is excellent in heat resistance but brittle. On the contrary, the required strength cannot be obtained.

Further, a foamed molded article having a degree of crystallinity exceeding 40% has a problem that the dimensional stability particularly in a high-temperature environment is reduced, and a gap is easily formed between the molded article and a floor material due to heat shrinkage. There is also. Therefore, in the present invention, it is preferable to use, as the above-mentioned thermoplastic polyester resin, a resin whose crystallization speed is particularly suppressed.

That is, the thermoplastic polyester resin in which the rate of crystallization is suppressed is smaller than the conventional PET or the like.
Even if the pre-expanded particles are exposed to a high temperature due to heating, the crystallinity of the pre-expanded particles is prevented from becoming excessively high, and the foam fusion property during in-mold foam molding is prevented from being significantly reduced. Therefore, it has excellent foam fusion property during in-mold foam molding,
Easily produce foamed moldings with excellent mechanical strength and dimensional stability under ordinary molding conditions using a general-purpose foaming molding machine without using a special foaming molding machine. It becomes possible.

The crystallization rate of the thermoplastic polyester-based resin is determined by using a differential scanning calorimeter (DSC) in accordance with the measurement method described in Japanese Industrial Standard JIS K7121. The temperature can be evaluated by the temperature at which crystallization occurs when the temperature is raised. That is, it can be said that the higher the crystallization peak temperature is, the more the resin requires a larger amount of heat to promote crystallization, that is, the lower the crystallization speed is.

Specifically, a predetermined amount of a thermoplastic polyester resin as a measurement sample is filled in a DSC measurement container, and while the temperature is raised at a rate of 10 ° C./min, the crystallization peak temperature is reduced. Measured. If the range of the crystallization peak temperature of the thermoplastic polyester resin measured in this way is about 130 ° C. or higher, the crystallization rate is suppressed as described above, and the thermoplastic polyester resin is a suitable thermoplastic polyester resin. It can be said that.

It is preferable that the crystallization peak temperature is 180 ° C. or lower, especially within the above range. When the crystallization peak temperature exceeds 180 ° C., the glass transition point of the resin becomes high, so that the condition width of the in-mold foaming becomes narrow, so that the molding becomes rather difficult. There is also a possibility that the shrinkage is likely to occur on the surface of the body, and a problem that a foam molded article having a good appearance cannot be obtained. In addition, a problem that the manufactured foam molded article becomes brittle may occur.

In consideration of the production of good pre-expanded particles and good foamed molded articles in consideration of the balance of the above properties, the peak temperature of the thermoplastic polyester resin should be within the above range. 132-175 ° C
The temperature is preferably about 135 to 170 ° C. The thermoplastic polyester-based resin satisfying such characteristics is not limited to the above-mentioned ones. For example, at least one component selected from the group consisting of isophthalic acid and cyclohexanedimethanol in all components is 0% in total. Those contained in the range of 0.5 to 10% by weight.

That is, as a dicarboxylic acid, a compound represented by the formula (1):

[0026]

Embedded image

Either the isophthalic acid represented by the formula (1) or cyclohexane dimethanol as the diol is used, or both of them are used in combination, and when either one is used alone, the content ratio of the one alone is reduced. If both are used together, the total content of
The above-mentioned thermoplastic polyester-based resin in the range of 0.5 to 10% by weight in all components is crystallized by the action of isophthalic acid and / or cyclohexanedimethanol to suppress the crystallization of the resin. Since the peak temperature is in the range of 130 to 180 ° C., it is possible to manufacture a good foam molded article that does not cause the various problems described above.

The content of isophthalic acid and / or cyclohexanedimethanol is in the above range in consideration of the balance between the above properties and the production of good pre-expanded particles and good foamed molded articles. Especially, it is preferably about 0.6 to 9.5% by weight, more preferably about 0.7 to 9% by weight.
Among the above, as the cyclohexanedimethanol, basically, two methanol moieties are respectively substituted at the 1-position and 4-position of the cyclohexane ring, a formula (2):

[0029]

Embedded image

The 1,4-cyclohexanedimethanol represented by the formula (1) is used, but the isomer in which two methanol moieties are substituted at other positions of the cyclohexane ring can be used together in a small amount. Among the other components constituting the thermoplastic polyester resin together with isophthalic acid and cyclohexanedimethanol, examples of the dicarboxylic acid include terephthalic acid and phthalic acid.

Examples of the diol component include ethylene glycol, α-butylene glycol (1,2-butanediol), β-butylene glycol (1,3-butanediol), and tetramethylene glycol (1,4-butanediol).
Butanediol), 2,3-butylene glycol (2,
3-butanediol), neopentyl glycol and the like.

In addition to the above-mentioned components, the raw materials of the thermoplastic polyester-based resin may include, for example, tricarboxylic acids such as tricarboxylic acids such as trimellitic acid and tetracarboxylic acids such as pyromellitic acid as acid components. Polyhydric carboxylic acids and their anhydrides, or alcohol components, such as triols such as glycerin, tetraols such as pentaerythritol, trihydric or higher polyhydric alcohols and the like, the crystallinity of the thermoplastic polyester resin and A small amount may be contained within a range that does not affect the crystallization speed and the like.

The above-mentioned thermoplastic polyester resin contains the above-mentioned components in a predetermined ratio, that is, as described above, isophthalic acid and / or cyclohexanedimethanol in a total amount of 0.5 to 10% by weight. It is produced by subjecting a raw material to a polycondensation reaction as in the conventional case. In addition, the thermoplastic polyester-based resin is obtained by mixing two or more kinds of thermoplastic polyester-based resins having different contents of isophthalic acid and / or cyclohexanedimethanol with respect to the content of isophthalic acid and / or cyclohexanedimethanol in all the components. Can be also produced by blending so that the total amount is in the range of 0.5 to 10% by weight, and melting and mixing under heating using, for example, an extruder.

According to this method, at the stage of producing the pre-expanded particles, the pre-expanded particles can be produced only by changing the mixing ratio of two or more kinds of thermoplastic polyester resins having different contents of isophthalic acid and / or cyclohexane dimethanol. The content ratio of both components in the pre-expanded particles can be adjusted. For this reason, there is an advantage that the adjustment operation can be simplified as compared with the case where the content ratio of both components is adjusted in the resin synthesis stage, and the specification can be flexibly changed.

Further, for example, by using a material recovered and reclaimed from used PET bottles or the like as one kind of thermoplastic polyester resin to be blended, effective reuse of resources and reduction of garbage can be achieved. Another advantage is that the cost of the pre-expanded particles can be reduced. In the above method, the two resins are melted and mixed sufficiently under heating so that each resin is alloyed by a transesterification reaction between two or more kinds of thermoplastic polyester resins to form a uniform thermoplastic polyester resin. Is preferred.

When the pre-expanded particles are mixed with a blowing agent under high-pressure melting using an extruder or the like as described later, pre-expanded, and then cut to produce, the two types of pre-expanded particles are used as described above. Melting of the above resins, production of a uniform thermoplastic polyester-based resin by mixing, is performed in the above-described extruder prior to mixing of the foaming agent, and then it is efficient to carry out the above-described production method continuously. Is preferable.

However, a uniform thermoplastic polyester resin prepared by melting and mixing two or more kinds of resins in advance using another apparatus is charged into an extruder, and pre-foamed by the above-mentioned production method. Particles may be produced. The thermoplastic polyester resin used in the present invention is used for melting and mixing at the time of producing pre-expanded particles, and at the time of producing a foamed molded article by in-mold foam molding using the produced pre-expanded particles. Considering moldability, its intrinsic viscosity (measuring temperature: 35 ° C, solvent: orthochlorophenol)
Is preferably about 0.6 to 1.5. <Pre-expanded Particles> Pre-expanded particles may be produced by impregnating the above-mentioned thermoplastic polyester-based resin with a foaming agent and then heating and pre-expanding the particles as in the conventional case.

However, the step of impregnating the thermoplastic polyester resin with a foaming agent is omitted to save time, cost and labor, and the crystallinity of the pre-expanded particles to be produced is further reduced, so that in-mold foam molding is performed. In order to further suppress the decrease in the foam fusion property at the time, as described above, the thermoplastic polyester resin is mixed with a foaming agent under high-pressure melting and prefoamed to obtain a prefoamed body. This is preferably cut to produce pre-expanded particles.

As a method for preliminarily foaming the thermoplastic polyester resin by mixing it with a foaming agent under high-pressure melting, an extrusion foaming method using an extruder is efficient and preferably employed. The extruder that can be used is not particularly limited, and is a single-screw extruder, a twin-screw extruder, or the like usually used for this type of extrusion foam molding, and may be a tandem type in which these are connected. An extruder having excellent melting and mixing capabilities is preferred.

Various extruders can be used. For example, there are an annular base, a flat base, a nozzle base, and a multi-nozzle base in which a plurality of nozzles are arranged. These bases can be used to make pre-foams of various shapes, such as sheet, plate and rod. Various methods are used to make the prefoamed body have the above-mentioned predetermined shape.

For example, in order to obtain a sheet-shaped prefoamed body, a cylindrical prefoamed body extruded from an annular die is made into a sheet shape by being advanced on a mandrel, or a sheet having a thickness extruded from a flat die. A plate-shaped prefoam may be formed into a sheet by a chill roll. Further, in order to obtain a thick plate-shaped prefoamed body, a method in which foaming is advanced while being in close contact with a pair of metal plates to obtain a predetermined thickness is employed.

As a method for cooling the prefoamed body, in addition to air cooling or water cooling, the prefoamed body is brought into contact with a temperature-controlled cooling device.
Various methods can be used. It is important that the prefoam be cooled as quickly as possible to prevent excessive crystallization. The pre-expanded particles of various shapes produced in this way are appropriately cut into a columnar shape, a square shape, a chip shape, or the like to complete the pre-expanded particles.

The cooling and cutting of the prefoamed body can be performed at an appropriate timing. For example, the prefoamed material extruded from the die is cooled by passing it through water at any time during foaming or after foaming is completed, and then the pelletizer is cooled.
It may be cut into a predetermined shape and size using a method such as the above. Alternatively, the prefoamed body immediately before or immediately after the completion of foaming, which has been extruded from the die, and immediately before cooling, may be immediately cooled and then cooled.

Further, the prefoamed material extruded in a sheet form may be once wound up in a roll shape by a winder or the like, stored, and then cut by a pulverizer or a cutter. The size of the pre-expanded particles thus produced is preferably about 0.5 to 5 mm as an average particle diameter. The degree of crystallinity of the pre-expanded particles is, as described above, using a general-purpose expansion molding machine, when foam molding is performed under ordinary molding conditions, excellent in the fusion property between particles, high mechanical strength. In consideration of obtaining a foamed molded product, the content is preferably about 8% or less.

In order to prevent the pre-expanded particles still having residual heat from being easily united when preparing the pre-expanded particles, the crystallinity is preferably about 1% or more. . The crystallinity of the pre-expanded particles is
Within the above range, it is particularly preferably about 1 to 7%, and more preferably about 1 to 6%.

The degree of crystallinity (%) is measured by using a differential scanning calorimeter (DSC) according to the measurement method described in Japanese Industrial Standards JIS K7121 in the same manner as the above-mentioned measurement of the crystallization peak temperature. From the measured heat of crystallization and heat of fusion, it is determined by the following equation.

[0047]

(Equation 1)

In the formula, the heat of fusion per mole of perfect crystalline PET is 26.9 kJ from the description in the Polymer Data Handbook [published by Baifukan]. Specifically, a predetermined amount of the pre-expanded particles as a measurement sample is filled in a DSC measurement container, and the heat of cold crystallization and the heat of fusion are measured while heating at a rate of 10 ° C./min, From the measurement results,
The crystallinity of the pre-expanded particles is determined based on the above equation.

The bulk density of the pre-expanded particles can be appropriately adjusted according to the density of a foamed article produced by subjecting the pre-expanded particles to in-mold foam molding. The density is preferred. Various additives may be added to the pre-expanded particles. Examples of the additive include, in addition to the foaming agent, a bubble regulator, a flame retardant, an antistatic agent, a colorant, and the like. Further, in order to improve the melting properties of the thermoplastic polyester resin, epoxy compounds such as glycidyl phthalate, acid anhydrides such as pyromellitic dianhydride, and acid anhydrides such as sodium carbonate.
A metal compound of group a or IIa or the like can be added alone or as a mixture of two or more as a modifier. In particular, these modifiers are effective not only to improve the foaming properties of the pre-expanded particles, but also to increase the expansion force of the pre-expanded particles in order to increase the closed cell ratio of the obtained expanded particles.

The foaming agent that can be used in the present invention is roughly classified into a solid compound which decomposes at a temperature higher than the softening point of the thermoplastic polyester resin to generate gas, and which is vaporized in the thermoplastic polyester resin when heated. It is classified into a liquid, an inert gas which can be dissolved in a thermoplastic polyester resin under pressure, and the like, and any of these may be used. Among them, examples of the solid compound include azodicarbonamide, dinitrosopentamethylenetetramine, hydrazoldicarbonamide, and sodium bicarbonate. As the liquid to be vaporized, for example, propane, n
-Butane, isobutane, n-pentane, isopentane,
Saturated aliphatic hydrocarbons such as hexane, aromatic hydrocarbons such as benzene, xylene and toluene, methyl chloride,
Examples include halogenated hydrocarbons such as Freon (registered trademark), and ether compounds such as dimethyl ether and methyl-tert-butyl ether. Further, examples of the inert gas include carbon dioxide and nitrogen.

The pre-expanded particles are mixed with a foaming agent under high-pressure melting using an extruder as described above, extruded and pre-expanded, and then cut to produce thermoplastic polyester resin pre-expanded particles. In such a case, a foaming agent which vaporizes and foams the molten resin at the moment when the molten resin is extruded from the die of the extruder and uses a blowing agent which takes away the heat of the molten resin, for example, a saturated aliphatic hydrocarbon, a halogenated hydrocarbon or the like is used. Is preferred. These foaming agents are preferable because they act to cool the molten thermoplastic polyester resin and have an effect of suppressing the crystallinity of the pre-expanded particles to be low.

The pre-expanded particles include, for example, a polyolefin resin such as a polypropylene resin, a thermoplastic elastomer such as a polyester resin, and the like, as long as they do not significantly affect the crystallinity and crystallization speed of the thermoplastic polyester resin. Polycarbonate, ionomer, etc. may be added. As a method of manufacturing a floor heating insulating material as a foam molded article using the pre-expanded particles, a pre-expanded particle is filled in a mold that can be closed but cannot be closed, and steam is introduced as a heating medium. In-mold foam molding is preferred.

As a heating medium at this time, hot air, oil, or the like can be used in addition to steam, but steam is most effective for efficient molding. The molded foam may be taken out of the mold after cooling. When performing in-mold foam molding with steam, foam molding may be performed under ordinary molding conditions using a general-purpose foam molding machine as described above. That is, after filling the pre-expanded particles in a mold, first, a low pressure [for example, a gauge pressure of 0.02MP.
a)] and blow steam into the mold for a certain time,
Discharge air between particles to the outside. Then, the pressure of the steam to be blown is increased (for example, about 0.08 MPa) to foam the pre-expanded particles in the mold and to fuse the particles together to obtain a foam molded article.

The pre-expanded particles are placed in a closed container in advance, and an inert gas such as carbon dioxide, nitrogen, or helium is injected thereinto. By maintaining in an atmosphere, the expansion force of the pre-expanded particles during in-mold foam molding in a mold can be further increased, and a good foam molded article can be obtained. In the foam molded article thus obtained, the fusion rate as a reference for the fusion property between the particles is preferably 40% or more, particularly preferably 50% or more, particularly preferably 60% or more, and the fusion rate is within this range. It can be said that it shows exceptionally excellent fusibility.

The degree of crystallinity is preferably about 20 to 40%, especially in consideration of dimensional stability in a high temperature environment. When the crystallinity is less than 20% or more than 40%, in any case, a dimensional change due to a temperature change becomes large, so that a gap is formed between the material and a floor material due to heat shrinkage. It will be easier. Further, those having a degree of crystallinity exceeding 40% become brittle, so that the required strength cannot be obtained as described above.

To adjust the degree of crystallinity of the foam molded article to a predetermined value within the above range, various methods can be adopted. For example, if the crystallinity of the foamed molded article after foam molding is lower than the target value, the foamed molded article is not taken out of the mold immediately, but is held in the mold for a while and heat-treated. The degree of crystallinity may be increased by such means.

If the degree of crystallinity of the foam molded article immediately after foam molding is close to the target value, the rise in crystallinity may be suppressed by rapidly cooling the mold. The crystallinity of the foam is obtained from the heat of cold crystallization and the heat of fusion measured in accordance with the measurement method described in Japanese Industrial Standard JIS K7121, similarly to the crystallinity of the pre-expanded particles described above.

The heat insulating material as the foamed molded article can be decomposed and recovered after being used for the floor heating device, and reused as pre-expanded particles or the like. By reusing the used foamed article in this way, it is possible to contribute to the effective recycling of resources and the reduction of dust, and it is also possible to reduce the cost of the foamed article.

[0059]

EXAMPLES Hereinafter, the advantages of the present invention will be specifically described with reference to examples and comparative examples. In addition, the crystallinity of the pre-expanded particles and the foam molded article produced using the same were determined from the results of measurement according to the measurement method described in Japanese Industrial Standard JIS K7121 as described above.

The density was measured by the following method. Measurement of Density According to the method described in Japanese Industrial Standard JIS K6767, the bulk density (g / c) of the pre-expanded particles is calculated by the following equation.
m ³ ) and the density (g / cm ³ ) of the foamed molded article were determined.

[0061]

(Equation 2)

Further, the following tests were performed on the foam molded articles as heat insulating materials manufactured in the following Examples and Comparative Examples, and their characteristics were evaluated. Measurement of 5% Compressive Strength In accordance with the method described in Japanese Industrial Standard JIS A9511, environmental temperature of each of the foamed molded articles of Examples and Comparative Examples is 0 to +
5% compressive strength (kg / cm ² ) in the temperature range of 70 ° C
And the ratio S ₂ / S ₁ was determined from the minimum value S ₁ and the maximum value S ₂ .

Measurement of fusion rate After the foamed molded articles of Examples and Comparative Examples were bent and broken in the thickness direction, the number of all foamed particles present in the fractured surface and the number of foamed particles of which the material itself was broken were The number of particles was counted. Then, a fusion rate (%), which is a reference of the fusion property between the particles, was determined by the following equation.

[0064]

(Equation 3)

Example 1 A thermoplastic polyester resin containing 75 parts by weight of polyethylene terephthalate resin pellets obtained by recycling a collected PET bottle and containing an isophthalic acid component and having a suppressed crystallization speed [content ratio of isophthalic acid: 7. 3% by weight,
Crystallization peak temperature 153.9 ° C, IV value 0.72] 25
Parts by weight, 0.3 parts by weight of pyromellitic dianhydride, and 0.03 parts by weight of sodium carbonate were extruded (diameter: 65 mm,
L / D ratio: 35] and the screw rotation speed 50r
pm, butane (n-butane / isobutane = 7/3) as a blowing agent was melted and mixed under the condition of a barrel temperature of 270 to 290 ° C. from a press-fit tube connected in the middle of the barrel.
The mixture was pressed at a rate of 1.2% by weight.

Next, the mixture in the molten state was charged into a multi-nozzle mold (straight line, diameter 0.8 mm) connected to the tip of the barrel.
15 nozzles each having a diameter of 15 mm were arranged], but after being extruded through each nozzle and prefoamed, 20 ° C.
In a cooling water bath held at Then, the pellet was cut by a pellet cutter while sufficiently removing water adhering to the cooled strand-shaped foam to produce pre-expanded particles.

The pre-expanded particles obtained had a major axis of 2.0 mm,
It was an elliptical column having a short diameter of 1.5 mm and a length of 2.0 mm, a bulk density of 0.12 g / cm ³ and a crystallinity of 4.9%. Next, the pre-expanded particles are put into a pressure-resistant closed container, compressed air is introduced thereinto, the inside of the container is pressurized to 0.5 MPa (gauge pressure), kept at room temperature for 5 hours, and then taken out of the closed container. Is immediately filled into a mold for producing a flat foamed molded article of about 900 mm × 300 mm × 10 mm as a heat insulating material for floor heating, and the mold is clamped. In this mold, a gauge pressure of 0.02 MPa is applied. Steam was introduced for 10 seconds and then steam having a gauge pressure of 0.08 MPa for 15 seconds to heat-expand the pre-expanded particles and simultaneously fuse them.

Immediately after the introduction of steam was completed, the surface temperature of the mold in contact with the foamed molded product was 118 ° C. Then, after holding in this state for 90 seconds (the surface temperature of the mold was lowered to 103 ° C.), it was cooled with water to produce a foamed molded article having the above dimensions and shape. The density of the obtained foamed molded article was 0.12 g / ml, and the crystallinity was 27.
5% and 28.4% at the center. The fusion rate is 84
% And good fusion property.

The 5% compressive strength of the foamed molded product is as follows, and the ratio S ₂ / S ₁ obtained from the minimum value S ₁ and the maximum value S ₂ is 1.04. Irrespective of the strength, it was confirmed to have a substantially constant strength. From this, it was also confirmed that a floor heating device incorporating such a heat insulating material had a good walking feeling without local depression. (5% compressive strength) 0 ° C .: 5.3 kg / cm ² 23 ° C .: 5.5 kg / cm ² 50 ° C .: 4.7 kg / cm ² 70 ° C .: 5.1 kg / cm ² Comparative Example 1 Foaming magnification 20 times A foam molded article having the same shape and the same dimensions as those of Example 1 was produced using foamed polypropylene. And that 5
The% compressive strength was measured as follows, and the ratio S ₂ / S ₁ obtained from the minimum value S ₁ and the maximum value S ₂ was 2.8.
5, it was found that the strength greatly fluctuated according to the temperature change. From this, it was also confirmed that the floor heating device incorporating such a heat insulating material is liable to cause deterioration of walking sensation due to local depression. (5% compressive strength) 0 ° C .: 3.7 kg / cm ² 23 ° C .: 2.7 kg / cm ² 50 ° C .: 1.8 kg / cm ² 70 ° C .: 1.3 kg / cm ² or more The results are shown in Table 1. .

[0070]

[Table 1]

As described in detail above, according to the present invention,
Improved floor heating insulation and floors with good walking sensation, which have almost constant strength regardless of temperature, so that it is hard to cause local depression especially in high temperature environment. It has a unique effect that a heating device can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an embodiment of a floor heating device of the present invention.

[Explanation of symbols]

 5 Insulation material for floor heating 6 Heating means

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[Procedure amendment]

[Submission date] July 29, 1999 (1999.7.2
9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

In the case where the ratio S ₂ / S ₁ exceeds 2, as described above, the compressive strength is greatly reduced under the environment where the temperature is temporarily increased at the start of the operation of the floor heating device, and However, there is a problem that a person is locally depressed, and as a result, walking feeling is deteriorated. Note the S ₂ / S ₁ is 1.
It is preferably 5 or less .

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0069

[Correction method] Change

[Correction contents]

The 5% compressive strength of the foamed molded product is as follows, and the ratio S ₂ / S ₁ obtained from its minimum value S ₁ and maximum value S ₂ is 1.17. Irrespective of the strength, it was confirmed to have a substantially constant strength. From this, it was also confirmed that a floor heating device incorporating such a heat insulating material had a good walking feeling without local depression. (5% compressive strength) 0 ° C .: 5.3 kg / cm ² 23 ° C .: 5.5 kg / cm ² 50 ° C .: 4.7 kg / cm ² 70 ° C .: 5.1 kg / cm ² Comparative Example 1 Foaming magnification 20 times A foam molded article having the same shape and the same dimensions as in Example 1 was produced using foamed polypropylene. And that 5
The% compressive strength was measured as follows, and the ratio S ₂ / S ₁ obtained from the minimum value S ₁ and the maximum value S ₂ was 2.8.
5, which indicates that the strength greatly fluctuates according to the temperature change. From this, it was also confirmed that the floor heating device incorporating such a heat insulating material is liable to cause deterioration of walking sensation due to local depression. (5% compressive strength) 0 ° C .: 3.7 kg / cm ² 23 ° C .: 2.7 kg / cm ² 50 ° C .: 1.8 kg / cm ² 70 ° C .: 1.3 kg / cm ² or more The results are shown in Table 1. .

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0070

[Correction method] Change

[Correction contents]

[0070]

[Table 1]

Claims (5)

[Claims] 1. The method according to claim 1, wherein the ambient temperature ranges from 0 to + 70 ° C.
The ratio S ₂ / S ₁ between the minimum value S ₁ and the maximum value S ₂ of the% compressive strength is 2
An insulating material for floor heating, comprising: a synthetic resin foam as described below. 2. A foam molded article obtained by in-mold foam molding of pre-expanded particles of a thermoplastic polyester resin,
The heat insulating material for floor heating according to claim 1, wherein the crystallinity is 20 to 40% and the fusion ratio is 40% or more. 3. A thermoplastic polyester resin comprising at least one component selected from the group consisting of isophthalic acid and cyclohexanedimethanol in all the components thereof.
The heat insulating material for floor heating according to claim 2, which is contained in a total amount of 0.5 to 10% by weight. 4. The heat insulating material for floor heating according to claim 2, wherein at least a part of the thermoplastic polyester resin is a recycled resin recovered from a used product. 5. A floor heating device comprising the heat insulating material for floor heating according to any one of claims 1 to 4, and heating means.