JP4487120B2 - Insulating material and manufacturing method thereof - Google Patents

Description

  The present invention relates to a heat insulating material comprising a polyurethane foam, and more specifically, a polyurethane foam having a low density and a large number of cells is produced by adding water as a foaming agent excessively, and then compressing the polyurethane foam heat transfer heat. Further, the present invention relates to a heat insulating material that is highly suppressed in convection heat transfer and has high heat insulating performance and is lightweight, and a method for manufacturing the same.

  For example, as an interior material used for a vehicle such as an automobile, a member having a high heat insulating performance, which is composed of a fiber body such as felt or a foam body such as polyurethane foam, is employed. This is one of the methods for improving the energy efficiency of the automobile itself, and as a result, achieving energy saving and low pollution, and is combining the internal combustion engine and the battery, which are attracting attention as part of recent global environmental measures. It is one of the important issues in automobiles and the like that have a so-called hybrid system and have improved energy efficiency.

  In general, in a heat insulating material having the same heat insulating performance, higher heat insulating performance can be achieved by increasing the amount of use (thickness). However, in this case, since the thickness of the heat insulating material increases in proportion to the heat insulating performance, in order to achieve high heat insulating performance, for example, the interior space of the vehicle in which the heat insulating material is disposed is sacrificed. Another problem arises, such as increasing the outer dimensions.

In order to avoid such a problem, there is a method in which (1) a fiber body or (2) a foam body as an interior material is compressed, thereby achieving both a constant heat insulation performance and a space saving property. However, in the case of manufacturing a heat insulating material by compression, (1) In a fibrous material such as felt having a high density as a material, there is a problem that the total weight is increased even if both heat insulating performance and space saving performance are achieved by high compression. (2) In a foam body such as polyurethane foam, the material density is as small as about 25 to 35 kg / m ³ , so the total weight is not a big problem, but the rebound rate is increased by compression, so-called springs Since a pack (bounce back) phenomenon occurs, there arises a problem that the dimensional accuracy when used as an interior material is deteriorated, or that it is difficult to attach to a portion where the thickness is small. In addition, the heat conductivity which concerns on the bone heat transfer which concerns on a heat insulating material by compressing becomes high, As a result, the problem that heat insulation property deteriorates is also pointed out.

In order to overcome the above problems and achieve the intended purpose, the heat insulating material according to the present invention is:
Against Po polyol and isocyanate, a catalyst, in a heat insulating material made of polyurethane foam obtained by mixing a secondary raw material including a foam stabilizer and water,
The isocyanate is mixed with the polyol so that the isocyanate index is in the range of 30 to 80, and the water is mixed in the range of 5 to 50 parts by mass with respect to 100 parts by mass of the polyol. The reaction amount of stoichiometric water with respect to the isocyanate calculated on the assumption that it reacts with the isocyanate, and the excess amount of water obtained by subtracting the reaction amount from the amount of water mixed with the polyol The ratio is set to a range of 0.20 to 6.50, and the density is in the range of 4 to ³⁰ kg / m ³ ,
By heating and compressing the foam body, the density is 10 to 50 kg / m ³ , the cell diameter in the compression direction is 1000 μm or less, and the thermal conductivity is less than 0.031 W / mK .

In order to overcome the above-mentioned problems and achieve the intended purpose, a method of manufacturing a heat insulating material according to another invention of the present application is
Against Po polyol and isocyanate, a catalyst, in the method for manufacturing the heat insulating material made of a polyurethane foam obtained by mixing a secondary raw material including a foam stabilizer and water,
While mixing the isocyanate so that the isocyanate index is in the range of 30 to 80 with respect to the polyol,
The water is mixed in the range of 5 to 50 parts by mass with respect to 100 parts by mass of the polyol, and the stoichiometric water with respect to the isocyanate calculated when it is assumed that all of the polyol reacts with the isocyanate. The ratio of the reaction amount and the excess amount of water obtained by subtracting the reaction amount from the amount of water mixed with the polyol is set in the range of 0.20 to 6.50, and the density is 4 to 30 kg. A foam body set in the range of / m ³ ,
A heat insulating material having a density of 10 to 50 kg / m ³ by heating and compressing the foam body, a cell diameter in the compression direction of 1000 μm or less, and a thermal conductivity of less than 0.031 W / mK. It is characterized by being manufactured.

  According to the heat insulating material and the method for producing the same according to the present invention, the bone foam heat transfer and the convection heat transfer are performed by compressing the low density and small cell diameter polyurethane foam produced by adding excessive water as a foaming agent. Is greatly suppressed, and a heat insulating material having high heat insulating performance and not bulky can be obtained. Further, because of its small density, it can be easily arranged in a narrow gap, and there is an effect that can be suitably used for so-called interference design.

  Next, the heat insulating material and the manufacturing method thereof according to the present invention will be described below with reference to the accompanying drawings together with the manufacturing method by giving preferred examples. The inventor of the present application compresses a polyurethane foam having a low density and a large number of cells, which is produced by excessively mixing water with a polyol, etc., taking advantage of the low density before compression, suppressing the weight without being bulky, And it discovered that the heat insulating material which can achieve the low heat conductivity by the low bone heat transfer derived from the thin frame | skeleton which comprises this foam, and the low convective heat transfer derived from a fine cell diameter is obtained.

The heat insulating material according to the example has a low density of ⁴ to ³⁰ kg / m ³ , preferably 4 to 20 kg / m ³ , that is, is thin by using excessively water as a foaming agent that is one of the raw materials. A foam body 12 (to be described later [0016]) having a porous structure composed of a skeleton is formed, and further, for example, this is compressed and molded under heating to crush a large number of cells defined by the skeleton. The cell volume is reduced to 1000 μm or less by reducing the space volume. And the manufacturing method of this heat insulating material is, as shown in FIG. 1, a raw material adjusting / mixing step S1 and a foaming step S2 for manufacturing the foam body 12 as a base of the heat insulating material, and a compression step S3 for compressing the foam body 12. Consists of The raw material adjustment / mixing step S1 and the foaming step S2 are basically substantially the same as Japanese Patent Application Laid-Open No. 2003-335834 (invention “soft polyurethane foam and manufacturing method thereof”) devised by the same applicant as the present application. Therefore, the details are omitted.

  As the polyol which is one of the main raw materials, polyether polyol obtained by adding alkylene oxide to a known initiator is used. Moreover, you may use the modified body obtained by making an ethylenically unsaturated monomer react with this polyether polyol. As the alkylene oxide, ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO), or the like is used alone or in combination. The number average molecular weight is not particularly limited as long as the foam body 12 can be formed, but is preferably 1200 to 8000.

  As the isocyanate, various known polyisocyanates such as aromatic, aliphatic or alicyclic can be used. In particular, in order to secure a small cell diameter, that is, a large number of cells, by the foam body 12 and the heat insulating material to be manufactured, rylene diisocyanate (TDI) having high compatibility with a polyol is preferably used. The blending amount of this isocyanate is set so that the isocyanate index is in the range of 30 to 80, preferably in the range of 30 to 75. When this value is less than 30, foaming may not be performed normally, cracking may occur, or foam collapse may occur. On the other hand, when it exceeds 80, the exothermic temperature at the time of foaming becomes high, and the possibility of spontaneous ignition increases.

  Among the auxiliary materials, as water as a foaming agent for determining a foaming ratio and achieving a low density, for example, normal water such as ion exchange water, tap water or distilled water is used. The compounding quantity of water is set to 5-50 mass parts with respect to 100 mass parts of polyol, Preferably it is set to the range of 7-50 mass parts. This excessive blending of water is to use water as a foaming agent, while having a role as a coolant that efficiently removes heat generated by foaming by vaporization of water. When the amount is less than 5 parts by mass, it becomes impossible to sufficiently suppress the heat generation during foaming and to reduce the density. On the other hand, when the amount exceeds 50 parts by mass, the amount of carbon dioxide generated as a foaming gas generated by the reaction between water and isocyanate increases, and a predetermined foam cannot be formed.

  Also, the amount of reaction of stoichiometric water with polyisocyanate calculated when all polyols react with isocyanate, and the excess amount of water obtained by subtracting the amount of reaction from the actual water content. The ratio (excess / reaction) is set between 0.10 and 7.00, preferably between 0.20 and 6.50. If this value is less than 0.10, the proportion of water involved in cooling decreases, and heat generation during foaming may not be suppressed. On the other hand, when this value exceeds 7.00, the amount of carbon dioxide generated by the reaction between water and isocyanate becomes too large, and a predetermined foam cannot be formed.

  As other auxiliary materials, catalysts, foam stabilizers such as silicone substances, foaming aids, flame retardants, antioxidants, ultraviolet absorbers, colorants or various diluents are added as necessary, The foam stabilizer is used in an amount of about 0.5 to 2.0 parts by weight with respect to 100 parts by weight of the polyol for the purpose of suitably holding the cells that are usually generated by a more severe foaming reaction due to the presence of excess water. It is desirable. If this amount is less than 0.5 parts by weight, the foam-forming ability of the raw material at the time of foaming is low, so that the cells serving as the cell base are not sufficiently retained, and a normal foam cannot be obtained. On the other hand, if the amount exceeds 2.0 parts by weight, the foam regulating ability of the raw material is too strong and the foaming gas is hardly discharged from the inside of the bubbles, so that the foam shrinks after completion of the foaming reaction.

  A small cell diameter, that is, a large number of cells is ensured by the foam body 12 and the heat insulating material to be manufactured, as described above ([0011]), by improving the compatibility between the polyol and the isocyanate, and this compatibility is improved. Is achieved by emulsifying a polyol and an isocyanate. This emulsification can be promoted by using a substance having a high EO (ethylene oxide) content as a foam stabilizer.

Then, by mixing and adding the above-mentioned raw materials in predetermined amounts, the density is 4 to 30 kg / m ³ , preferably 4 to 20 kg / m ³ , and the cell diameter is 3000 μm or less. The foam body 12 is manufactured. In the production of the foam body 12, since the exothermic temperature associated with the violent foaming reaction can be set to 160 ° C. or less due to the presence of excess water, the occurrence of scorch and the like and the risk of fire can be reduced.

Next, as shown in FIG. 2, the compression step S3 to be performed is a well-known method for the foam body 12 (see FIG. 2 (a)) manufactured through the raw material adjustment / mixing step S1 and the foaming step S2. This is a step of obtaining a heat insulating material 10 (see FIG. 2D) by applying compression under heating using a compression device such as a hot press device (see FIGS. 2B and 2C). By performing this compression step S3, the foam body 12 is compressed to about 1/10 at the maximum, that is, the compression ratio is set to 10 times or less. When this magnification exceeds 10 times, bone heat conduction (described later [0019]) becomes large, and the heat insulating property is lowered. Since the heat insulating material 10 according to the present invention is used as an interior material for a vehicle such as an automobile, the density thereof is preferably about 25 to 35 kg / m ³ as described in the background art (see [0004]). The In the present invention, a direction in which the foam body 12 indicated by an arrow in FIGS. 2C and 2D is compressed is referred to as a compression direction.

  This compression is carried out at a temperature in the range of 80 to 220 ° C. and a time in the range of 30 to 250 seconds. If neither of them reaches the minimum temperature or the minimum time, the compressed heat insulating material 10 cannot maintain its compressed state. On the other hand, if the maximum temperature or the maximum time is exceeded, scorch or the like occurs in the polyurethane foam forming the heat insulating material 10. Or the foam body 12 may be melted or a fire may be caused in some cases. This compression is performed in a pair of opposite directions in the vertical direction.

  Considering how heat is transferred in the body, that is, the heat transfer mode, (1) conduction and (2) convection can be mentioned. Then, (1) conduction corresponds to so-called bone heat transfer that travels through the skeleton of the polyurethane foam constituting the heat insulating material 10, and (2) convection corresponds to convection heat transfer due to air convection in the cell 16. And (1) When the heat transfer degree in the substance is the same, the bone heat transfer greatly depends on the area perpendicular to the heat transfer direction, that is, the thickness of the skeleton forming the polyurethane foam. Also, (2) convection heat transfer is the length of the space in the convection direction, that is, if the object to be convected is the same (for example, air), that is, heat insulation in the cell This greatly depends on the length of the space in the direction (hereinafter referred to as the heat insulation direction) along the line segment indicating the shortest distance from the inside, that is, the cell diameter. In general, since the thermal conductivity is used for an index indicating the heat insulation performance, this index is also used in the present invention. The thermal conductivity is determined by both (1) bone heat transfer and (2) convective heat transfer.

  In other words, in order to improve the heat insulation, it is only necessary to make the skeleton of the polyurethane foam constituting the heat insulating material 10 thin and to reduce the cell diameter (space length) along the heat insulation direction. Since the heat insulating material 10 according to the present invention is produced with excess water as described above ([0012]), the foaming reaction is greatly prevalent, and the skeleton forming the polyurethane foam is compared with the ordinary polyurethane foam. And become thin. Also, by using the required silicone-based material for the foam stabilizer, the number of cells of the foam body 12 is increased, that is, the cell diameter is smaller than that of ordinary polyurethane foam, and the cells are compressed by further compression. The cell diameter in the direction is made smaller, that is, the cell diameter (space length) in the compression direction is made smaller. If the cell diameter (space length) in the compression direction is reduced, the amount of convection gas in order to conduct heat in the inside will also decrease, and convection itself will not be performed well. (2) Convection Heat transfer can be small.

  Therefore, if the compression direction of the foam body 12 is matched with the heat insulation direction, both (1) bone heat transfer and (2) convective heat transfer described above can be greatly reduced. As shown in FIG. 3, basically (1) When the skeleton is made thin to reduce bone heat transfer (FIG. 3 (a) → FIG. 3 (b)), the cell diameter in the compression direction is the same if the skeleton structure is the same. Since (the length of the space) becomes large, (2) convective heat transfer becomes high accordingly. In this way, since the two (1) and (2) cancel each other, the overall thermal conductivity does not change much. However, in the case of the heat insulating material 10 according to the present invention, a reduction in both (1) bone heat transfer and (2) convective heat transfer can be achieved, so that high heat insulating performance can be ensured. And, as in the present invention, when compressing the foam body 12 to reduce the cell diameter (space length), the skeletal thickness does not change before and after compression, so (1) change the bone heat transfer Without (2) convective heat transfer, that is, thermal conductivity can be reduced.

By the way, (1) bone heat transfer and (2) convection heat transfer, as shown in FIG. 4, with a density of about 30 kg / m ³ as a boundary, (2) It is empirically known that (1) bone heat transfer has a greater influence in the high density region. For this reason, when considering interior materials for vehicles such as automobiles, the density after compression needs to be about 35 kg / m ³ or less, preferably about 30 kg / m ³ or less. In other words, in this density region, (2) convective heat transfer has a greater effect on the overall thermal conductivity, and therefore the reduction of the cell diameter (space length) in the heat insulation direction by compression of the foam body 12 has a great effect. I can expect.

Since the heat insulating material 10 is obtained by compressing the foam body 12 as described above, the cell diameter in the compression direction of the heat insulating material 10 is basically calculated by the cell diameter / compression ratio of the foam body 12 before compression. . When the heat insulating material 10 according to the present invention is used, the density of the foam body 12 that is a group to be compressed is in the range of ^{4 to} 20 kg / m ³ as described above, and the polyurethane foam manufactured by a normal manufacturing method is used. Since it is 25-30 kg / m ³ or less which is a general lower limit density, when the density of the heat insulating material 10 is set to the same level as the heat insulating material made of a conventional polyurethane foam, the compression ratio is 7.5 times at the maximum. It will be about. That is, when the heat insulating material 10 according to the present invention is used, when the density is set to be equal to that of a conventional heat insulating material made of polyurethane foam, the cell diameter in the compression direction is at least 3000 μm / 7.5 times = 400 μm or less. It is possible. In general, the foam body 12 of about 10 kg / m ³ is manufactured and compressed because of its ease of manufacture, and the compression ratio is suitably about 2.5 to 3 times, so the number of cells is 3000 μm / 2.5 to 3 times = 1000 to 1200 μm or less.

  As described above, the heat insulating material 10 according to the present invention has a small density, that is, can be easily compressed. For example, a slight gap between the skin and the core material of the molded ceiling in an automobile interior, air conditioning, etc. It is possible to arrange the duct around the duct without troublesome work. That is, it can be easily attached to a portion requiring interference design. Moreover, since the heat insulation effect becomes high, so that the heat insulating material 10 is high in the compression magnification, in use under such interference, higher heat insulation can be provided.

(Experimental example)
Below, the experiment example which compared the density, thermal conductivity, etc. before and after the compression about the heat insulating material using the polyurethane foam which concerns on this invention, and the heat insulating material using a normal polyurethane foam is shown.

The following raw materials are used according to Table 1 described below, and five types of polyurethane foams (foam bodies 12) according to A to E are respectively produced. A specific manufacturing method is as follows. That is, first, all raw materials other than isocyanate were stirred at a predetermined quantitative ratio using a hand mixer, and then the isocyanate was mixed according to the isocyanate index described in Table 1, and 540 g of this mixture was added to a foaming box (length 300 mm × width 400 mm × height). And foamed and cured to form a polyurethane foam. The obtained polyurethane foam was cut into the thickness (mm) described in Table 2, and further compressed to the thickness (mm) described in Table 2 (Example) and Table 2 (Comparative Example). To 5 and Comparative Examples 1 and 2 were produced. The thermal conductivity (W / mK) before and after compression was measured. Also, density (kg / m ³ ) and cell diameter before and after compression (μm (cell diameter in the compression direction after compression)), porosity (%), and heating temperature and heating time during compression It was measured. For reference, the same measurement was performed for a heat insulating material made of a general nonwoven fabric (trade name: Synthalate; manufactured by Sumitomo 3M), and the results are shown in Table 2 (Example) and Table 3 (Comparative Example).

(Raw material)
・ Polyol: Trade name GP3000 (number average molecular weight 3000, equivalent weight 1000); manufactured by Sanyo Chemical Industries ・ Isocyanate: trade name T-80 (TDI); manufactured by Nippon Polyurethane ・ Foaming agent: water (ion-exchanged water)
・ Catalyst A: Trade name 33LV; Sankyo Air Products ・ Catalyst B: Trade name MRH110; Johoku Chemical ・ Foam stabilizer A: Trade name L-5420; Nihon Unicar ・ Foam stabilizer B: Trade name B8110; Gold Schmidt Made

(results of the experiment)
The results obtained from the experiments are shown in Tables 2 and 3 above. From the results shown in Table 2 and Table 3, a foam body having an extremely thin skeleton produced by excessively mixing 5 to 50 parts by mass of a blowing agent (water) with respect to 100 parts by mass of a polyol is compressed. Thus, the heat insulating material having a small cell diameter determines (1) bone heat transfer and (2) convective heat transfer, which determine the thermal conductivity, and has a high heat insulating property of 0.031 W / mK or less. It was confirmed that the density of 35 kg / m ³ or less was achieved together. It was also confirmed that a very high heat insulating property of 0.03 W / mK or less can be secured by increasing the compression ratio.

It is process drawing which shows the manufacturing method of the heat insulating material which concerns on the suitable Example of this invention. It is a state figure which shows the compression process of the heat insulating material which concerns on an Example. It is the schematic which shows the relationship between the cell diameter in the structure provided with the same frame | skeleton structure, and the thickness of frame | skeleton. It is a graph which shows roughly the relationship in the influence in the kind of heat transfer, and a density.

Explanation of symbols

10 Thermal insulation material 12 Foam body

Claims (6)

Against Po polyol and isocyanate, a catalyst, in a heat insulating material made of polyurethane foam obtained by mixing a secondary raw material including a foam stabilizer and water,
The isocyanate is mixed with the polyol so that the isocyanate index is in the range of 30 to 80, and the water is mixed in the range of 5 to 50 parts by mass with respect to 100 parts by mass of the polyol. The reaction amount of stoichiometric water with respect to the isocyanate calculated on the assumption that it reacts with the isocyanate, and the excess amount of water obtained by subtracting the reaction amount from the amount of water mixed with the polyol A ratio of 0.20 to 6.50, and a foam body (12) having a density in the range of 4 to ³⁰ kg / m ³ ,
By heating and compressing the foam body (12), the density was 10 to 50 kg / m ³ , the cell diameter in the compression direction was 1000 μm or less, and the thermal conductivity was less than 0.031 W / mK. > Insulation characterized by that. The heat insulating material according to claim 1, wherein the density after compression is 35 kg / m ³ or less and the cell diameter in the compression direction is 800 μm or less. Against Po polyol and isocyanate, a catalyst, in the method for manufacturing the heat insulating material made of a polyurethane foam obtained by mixing a secondary raw material including a foam stabilizer and water,
While mixing the isocyanate so that the isocyanate index is in the range of 30 to 80 with respect to the polyol,
The water is mixed in the range of 5 to 50 parts by mass with respect to 100 parts by mass of the polyol, and the stoichiometric water with respect to the isocyanate calculated when it is assumed that all of the polyol reacts with the isocyanate. The ratio of the reaction amount and the excess amount of water obtained by subtracting the reaction amount from the amount of water mixed with the polyol is set in the range of 0.20 to 6.50, and the density is 4 to 30 kg. A foam body (12) set in a range of / m ³ is manufactured,
By heating and compressing the foam body (12), the density is in the range of 10 to 50 kg / m ³ , the cell diameter in the compression direction is 1000 μm or less, and the thermal conductivity is less than 0.031 W / mK. A method for manufacturing a heat insulating material, characterized in that the heat insulating material (10) is manufactured. The density of the said foam body (12) is a manufacturing method of the heat insulating material of Claim 3 set to the range of 4-20 kg / m < ³ >.   The said compression is a manufacturing method of the heat insulating material of Claim 3 or 4 implemented so that a cell diameter may make the cell diameter 800 micrometers or less in the compression direction. The method for manufacturing a heat insulating material according to any one of claims 3 to 5 , wherein the compression ratio is set to 10 times or less.

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